Scientific American Supplement No. 344 (page 2)

COMPOUND BEAM ENGINE.

The engine represented in Figs. 1 to 4 herewith is intended for a mill, and is of 530 to 800 indicated horse-power, the pressure being seven atmospheres, and the number of revolutions forty-five per minute. As will be seen by the drawing each cylinder is placed in a separate foundation plate, the two connecting rods acting upon cranks keyed at right angles upon the shaft, W, which carries the drum, T. The high-pressure cylinder, C, is 760 mm diameter, the low pressure cylinder being 1,220 mm. diameter, and the piston speed 2.28 m. The drum, which also fulfills the purpose of a fly wheel, is provided with twenty-eight grooves for ropes of 50 mm. diameter. With the exception of the cylinders, pistons, valves, and valve chests, the engines are of the same size, corresponding to the equal maximum pressures which come into action in each cylinder, and in this respect alone the engine differs in principle from an ordinary twin machine.

[Illustration: BORSIG’S IMPROVED COPOUND BEAM ENGINE. FIG. 1]

The steam passes from the stop-valve, A, Fig. 4, through the steam pipe, D, to the high pressure cylinder, C, and having done its work, goes into the receiver, R, where it is heated. From the receiver it is led into the low-pressure cylinder, C1, and thence into the condenser. Provision is made for working both engines independently with direct steam when desired, suitable gear being provided for supplying steam of the proper pressure to the condensing engine, so that each engine shall perform exactly the same amount of work. The starting gear consists of a hand-wheel, H, which controls the stop valve, A, and of another h, which opens the valves for the jackets of the cylinders and receiver. The hand-wheel, h1 and h2, govern the valves, which turn the steam direct into the two cylinders. There are also lever, g, which opens the principal injection cock, H1, and the auxiliary injection cock, H2, the function of which is to assist in forming a speedy vacuum, when the engine has been standing for some time.

[Illustration: BORSIG’S IMPROVED COPOUND BEAM ENGINE. FIG. 2]

The drum is 6.08 m. diameter, the breadth being 2.04 m., with a total weight of 33,000 kilos. The beams are of cast iron with balance weights cast on. The connecting rods and cross beams are of wrought iron, and the cranks, crank shaft, piston rods, valve rods, etc., of steel. The bed-plate for the main shaft bearings are cast in one piece with the standards for the beam, which are connected firmly together by the center bearing, M M1, which is cast in one piece, and also by the diagonal bracing piece, N N1. The construction of the cylinder and valve chests is shown in Fig. 1. The working cylinder is in the form of a liner to the cylinder, thus forming the steam jacket, with a view to future renewal. This lining has a flange at the lower part for bolting it down, being made steam-tight by the intervention of a copper packing ring. There is a similar ring at the upper part which is pressed down by the cylinder cover. The latter is cast hollow and strengthened by ribs. The pistons are provided with cast iron double self-expanding packing rings. For preventing accidents by condensed water, spring safety valves, ss and s1 s1, are connected to the valve chests. The valve gear, which is arranged in the same manner for both cylinders, is actuated by shafts, w and w1, rotated by toothed wheels as shown. Motion is communicated from the way-shafts, w and w1, by the eccentrics, and the eccentric rods, e1 e2 e3 e4, and the levers and rods belonging thereto, to the short steam valve rocking shafts levers, f1 f2 f3 f4, and the exhaust valve rocking shafts, k1 k2 k3 k4, the bearings of which are carried on brackets above the valve chests, which, being furnished with tappet levers, raise and lower the valves.

[Illustration: BORSIG’S IMPROVED COPOUND BEAM ENGINE. FIG. 3]

The valves are conical, double-seated, and of cast iron, and the inlet and outlet valves are placed the one above the other, the seats being also conically ground and inserted through the cover of the valve chest. Both inlet and outlet valves are actuated from above, and are removable upward, an arrangement which admits of the valves being more easily examined than when the two are actuated from different sides of the valve chest. To carry out this idea the inlet valves are furnished with two guides, which, passing upward through the stuffing-box, are attached to a hard steel cross piece, which receives the action of a bent catch turning on a pin attached to the levers, t1, t2, t3, t4. The exhaust valves, on the contrary, have only one guide each, which passes upward through the seat of the admission valve, through the valve itself by means of a collar, and through the stuffing-box. It is furnished with hard steel armatures, through which the levers, z1 z2, Fig. 3, act upon the exhaust valves.

[Illustration: BORSIG’S IMPROVED COPOUND BEAM ENGINE. FIG. 4]

The governor effects the acceleration or retardation of the loosening of the catch actuating the steam valve by means of hard steel projections on the shaft, v1, the position of which, by means of levers, is regulated by the governor, which in its highest position does not allow the lifting of the inlet valve at all. The regulation of the expansion by the governor from 0 to 0.45 takes place generally only in the case of the high-pressure cylinder, while the low-pressure cylinder has a fixed rate of expansion. Only when the low-pressure cylinder is required to work with steam direct from the boiler is the governor applied to regulate the expansion in it. An exact action in the valve guides and a regular descent is secured by furnishing them with small dash pot pistons working in cylinders. Into them the air is readily admitted by a small India-rubber valve, but the passage out again is controlled at pleasure.–_The Engineer_.

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TO DETECT ALKALIES IN NITRATE OF SILVER–Stolba recommends the salt to be dissolved in the smallest quantity of water, and to add to the filtered solution hydrofluosilicic acid, drop by drop. Should a turbidity appear an alkaline salt is present. But should the liquid remain limpid, an equal volume of alcohol is to be added, which will cause a precipitate in case the slightest trace of an alkali be present.

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POWER HAMMERS WITH MOVABLE FULCRUM.

[Footnote: Paper read before the Institution of Mechanical Engineers.–_Engineering_.]

By DANIEL LONGWORTH, of London.

The movable-fulcrum power hammer was designed by the writer about five and a half years ago, to meet a want in the market for a power hammer which, while under the complete control of only one workman, could produce blows of varying forces without alteration in the rapidity with which they were given. It was also necessary that the vibration and shock of the hammer head should not be transmitted to the driving mechanism, and that the latter should be free from noise and liability to derangement. The various uses to which the movable fulcrum hammers have been put, and their success in working[1]–as well as the importance of the general subject which includes them, namely, the substitution of stored power for human effort–form the author’s excuse for now occupying the time of the meeting.

[Footnote 1: The hammers have been for some years used by A. Bamlett, of Thirsk; the American Tool Company, of Antwerp; Messrs. W.&T. Avery, of Birmingham; Pullar & Sons, of Perth; Salter & Co., of West Bromwich; Vernon Hope & Co., of Wednesbury, etc.; and also for stamps by Messrs. Collins & Co., of Birmingham, etc.]

Until these hammers were introduced, no satisfactory method had been devised for altering the force of the blow. The plan generally adopted was to have either a tightening pulley acting on the driving belt, a friction driving clutch, or a simple brake on the driving pulley, put in action by the hand or foot of the workman. Heavy blows were produced by simply increasing the number of blows per minute (and therefore the velocity), and light blows by diminishing it–a plan which was quite contrary to the true requirements of the case. To prevent the shock of the hammer head being communicated to the driving gear, an elastic connection was usually formed between them, consisting of a steel spring or a cushion of compressed air. With the steel spring, the variation which could be given in the thickness of the work under the hammer was very limited, owing to the risk of breaking the spring; but with the compressed air or pneumatic connection the work might vary considerably in thickness, say from 0 to 8 in. with a hammer weighing 400lb. The pneumatic hammers had a crank, with a connecting rod or a slotted crossbar on the piston-rod, a piston and a cylinder which formed the hammer-head. The piston-rod was packed with a cup leather, or with ordinary packing, the latter required to be adjusted with the greatest nicety, otherwise the piston struck the hammer before lifting it, or else the force of the blow was considerably diminished. As the piston moved with the same velocity during its upward and downward strokes, and, in the latter, had to overtake and outrun the hammer falling under the action of gravity, the air was not compressed sufficiently to give a sharp blow at ordinary working speeds, and a much heavier hammer was required than if the velocity of the piston had been accelerated to a greater degree.

As it is impossible in the limits of this paper to describe all the forms in which the movable fulcrum hammers have been arranged, two types only will be selected taken from actual work; namely, a small planishing hammer, and a medium-sized forging hammer.[1]

[Footnote 1: To the makers, Messrs. J. Scott Rawlings & Co, of Birmingham, the author is indebted for the working drawings of these hammers.]

The small planishing hammer, Figs. 1 to 3, next page, is used for copper, tin, electro, and iron plate, for scythes, and other thin work, for which it is sufficient to adjust the force of the blow once for all by hand, according to the thickness and quality of the material before commencing to hammer it. The hammer weighs 15 lb., and has a stroke variable from 21/2 in. to 91/2 in., and makes 250 blows per minute. The driving shaft, A, is fitted with fast and loose belt pulleys, the belt fork being connected to the pedal, P, which when pressed down by the foot of the workman, slides the driving belt on to the fast pulley and starts the hammer; when the foot is taken off the pedal, the weight on the latter moves the belt quickly on to the loose pulley, and the hammer is stopped. The flywheel on the shaft, A, is weighted on one side, so that it causes the hammer to stop at the top of its stroke after working; thus enabling the material to be placed on the anvil before starting the hammer. The movable fulcrum, B, consists of a stud, free to slide in a slot, C, in the framing, and held in position by a nut and toothed washer. On the fulcrum is mounted the socket, D, through which passes freely a round bar or rocking lever, E, attached at one end to the main piston, F, of the hammer, G, and having at the other extremity a long slide, H, mounted upon it. This slide is carried on the crank-pin, I, fastened to the disk, J, attached to the driving shaft, A. The crank-pin, in revolving, reciprocates the rocking lever, E, and main piston, F, and through the medium of the pneumatic connection, the hammer, G. The slide, H, in revolving with the crank-pin, also moves backward and forward along the rocking lever, approaching the fulcrum, B, during the down-stroke of the hammer, and receding from it during the up-stroke. By this means the velocity of the hammer is considerably accelerated in its downward stroke, causing a sharp blow to be given while it is gently raised during its upward stroke.

To alter the force of the blow, the hammer, G, is made to rise and fall through a greater or less distance, as may be required, from the fixed anvil block, K, after the manner of the smith giving heavy or light blows on his anvil. It is evident that this special alteration of the stroke could not be obtained by altering the throw of a simple crank and connecting rod; but by placing the slot, C, parallel with the direction of the rocking lever, E, when the latter is in its lowest position, with the hammer resting on the anvil, and with the crank at the top of its stroke, this lowest position of the rocking lever and hammer is made constant, no matter what position the fulcrum, B, may have in the slot, C. To obtain a short stroke, and consequently a light blow, the fulcrum is moved in the slot toward the hammer, G; and to produce a long stroke and heavy blow the fulcrum is moved in the opposite direction.

Fig. 3 gives the details of the pneumatic connection between the main piston and the hammer, in which packing and packing glands are dispensed with. The hammer, G, is of cast steel, bored out to fit the main piston, F, the latter being also bored out to receive an internal piston, L. A pin, M, passing freely through slots in the main piston, F, connects rigidly the internal piston, L, with the hammer, G. When the main piston is raised by the rocking lever, the air in the space, X, between the main and internal pistons, is compressed, and forms an elastic medium for lifting the hammer; when the main piston is moved down, the air in the space, Y, is compressed in its turn, and the hammer forced down to give the blow. Two holes drilled in the side of the hammer renew the air automatically in the spaces, X and Y, at each blow of the hammer.

Figs. 4 to 6, on the next page, represent the medium size forging hammer, for making forgings in dies, swaging and tilting bars, and plating edged tools, etc.

The hammer weighs 1 cwt., has a stroke variable from 4 in. to 141/2 in., and gives 200 blows per minute; the compressed air space between the main piston and the hammer is sufficiently long to admit forgings up to 3 in. thick under the hammer.

To make forgings economically, it is necessary to bring them into the desired form by a few heavy blows, while the material is still in a highly plastic condition, and then to finish them by a succession of lighter blows. The heavy blows should be given at a slower rate than the lighter ones, to allow time for turning the work in the dies or on the anvil, and so to avoid the risk of spoiling it. In forging with the steam hammer the workman requires an assistant, who, with the lever of the valve motion in hand, obeys his directions as to starting and stopping, heavy or light blows, slow or quick blows, etc; the quickest speed attainable depending on the speed of the arm of the assistant. In the movable-fulcrum forging hammer the operations of starting and stopping, and the giving of heavy or light blows, are under the complete control of one foot of the workman, who requires therefore no assistant; and by properly proportioning the diameter of the driving pulley and size of belt to the hammer, the heavy blows are given at a slower rate than the light ones, owing to the greater resistance which they offer to the driving belt.

In this hammer the pneumatic connection, the arrangements for the starting, stopping, and holding up of the hammer, as well as those for communicating the motion of the crank-pin to the hammer by means of a rocking lever and movable fulcrum, are similar to those in the planishing hammer, differing only in the details, which provide double guides and bearings for the principal working parts.

[Illustration: LONGWORTH’S POWER HAMMER WITH MOVABLE FULCRUM.]

The movable fulcrum, B, Figs. 4 and 5, consists of two adjustable steel pins, attached to the fulcrum lever, Q, and turned conical where they fit in the socket, D. The fulcrum lever is pivoted on a pin, R, fixed in the framing of the machine, and is connected at its lower extremity to the nut, S, in gear with the regulating screw, T. The to-and-fro movement of the fulcrum lever, Q, by which heavy or light blows are given by the hammer, is placed under the control of the foot of the workman, in the following manner: U is a double-ended forked lever, pivoted in the center, and having one end embracing the starting pedal, P, and the other end the small belt which connects the fast pulley on the driving shaft, A, with the loose pulley, V, or the reversing pulleys, W and X. These are respectivly connected with the bevel wheels, W_{1}, and X_{1}, gearing into and placed at opposite sides of the bevel wheel, Z, on the regulating screw in connection with the fulcrum lever. When the workman places his foot on the pedal, P, to start the hammer, he finds his foot within the fork of the lever, U; and by slightly turning his foot round on his heel he can readily move the forked lever to right or left, so shifting the small belt on to either of the reversing pulleys, W or X, and causing the regulating screw, T, to revolve in either direction. The fulcrum lever is thus caused to move forward or backward, to give light or heavy blows. By moving the forked lever into mid position, the small belt is shifted into its usual place on the loose pulley, V, and the fulcrum remains at rest. To fix the lightest and heaviest blow required for each kind of work, adjustable stops are provided, and are mounted on a rod, Y, connected to an arm of the forked lever. When the nut of the regulating screw comes in contact with either of the stops, the forked lever is forced into mid position, in spite of the pressure of the foot of the workman, and thus further movement of the fulcrum lever, in the direction which it was taking, is prevented. The movable fulcrum can also be adjusted by hand to any required blow, when the hammer is stopped, by means of a handle in connection with the regulating screw.

In conclusion the author wishes to direct attention to the fact, that in many of our largest manufactories, particularly in the midland counties, foot and hand labor for forging and stamping is still employed to an enormous extent. Hundreds of “Olivers,” with hammers up to 60 lb. in weight, are laboriously put in motion by the foot of the workman, at a speed averaging fifty blows per minute; while large numbers of stamps, worked by hand and foot, and weighing up to 120 lb., are also employed. The low first cost of the foot hammers and stamps, combined with the system of piece work, and the desire of manufacturers to keep their methods of working secret, have no doubt much to do with the small amount of progress that has been made; although in a few cases competition, particularly with the United States of America, has forced the manufacturer to throw the Oliver and hand-stamp aside, and to employ steam power hammers and stamps. The writer believes that in connection with forging and stamping processes there is still a wide and profitable field for the ingenuity and capital of engineers, who choose to occupy themselves with this minor, but not the less useful, branch of mechanics.

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THE BICHEROUX SYSTEM OF FURNACES APPLIED TO THE PUDDLING OF IRON.

Since the year 1872, the large iron works at Ougree, near Liege, have applied the Bicheroux system of furnaces to heating, and, since the year 1877, to puddling. The results that have been obtained in this last-named application are so satisfactory that it appears to us to be of interest to speak of the matter in some detail.

The apparatus, which is shown in the opposite page, consists of three distinct parts: (1) a gas generator; (2) a mixing chamber into which the gases and air are drawn by the natural draught, and wherein the combustion of the gases begins; and (3) a furnace, or laboratory (not represented in the figure), wherein the combustion is nearly finished, and wherein take place the different reactions of puddling. These three parts are given dimensions that vary according to the composition of the different coals, and they may be made to use any sort of coal, even the fine and schistose kinds which would not be suitable for ordinary puddling. The gases and the air necessary for the combustion of these being brought together at different temperatures, and being drawn into the mixing chamber through the same chimney, it will be seen that the dimensions of the flues that conduct them should vary with the kind of coal used; and the manner in which the gases are brought together is not a matter of indifference.

[Illustration: THE BICHEROUX SYSTEM OF FURNACE.

Vertical Section, and Horizontal Section through MNOPQR]

The gas generator consists of a hopper, A, into which drops, through small apertures a, the coal piled up on the platform, D. These apertures are closed with coal or bricks. The bottom of the generator is formed of a small standing grate. The coal, on falling upon a mass in a state of ignition, distills and becomes transformed into coke, which gradually slides down over a grate to produce afterward, through its own combustion, a distillation of the coal following it. But as these are features found in all generators we will not dwell upon them.

The gases that are produced flow through a long horizontal flue, B, into a vertical conduit, E, into which there debouches at the upper part a series of small orifices, F, that conduct the air that has been heated. The gases are inflamed, and traverse the furnace c (not shown in the cut), from whence they go to the chimney. Before the air is allowed to reach the intervening chamber it is made to pass into the sole of the furnace and into the walls of the chamber, so that to the advantage of having the air heated there is joined the additional one of having those portions of the furnace cooled that cannot be heated with impunity.

The incompletely burned gases that escape from the furnace are utilized in heating the boilers of the establishment. The dimensions given these furnaces vary greatly according to the charge to be used. All the results at Ougree have been obtained with 400 kilogramme charges, and the dimensions of the gas generators have been calculated for Six-Bonniers coal, which does not yield over 20 per cent. of gas.

The advantages of this system, which permits of expediting all the operations of puddling, are as follows:

1. A notable economy in fuel, both as regards quantity and quality.

2. Economy resulting from diminution in the waste of metal, with a consequent improvement in the quality of the products obtained.

3. Diminution in cost of repairs.

4. Less rapid wear in the grates.

5. Improvement in the conditions of the work of puddling.

As regards the first of these advantages, it may be stated that the puddling of ordinary Ougree forge iron, which required with other furnaces 900 to 1,000 kilogrammes of coal, is now performed with less than 600 kilogrammes per ton of the iron produced. The puddling of fine grained iron which required 1,300 to 1,500 kilogrammes of coal is now done with 800. So much for quantity; as for quality the system presents also a very marked advantage in that it requires no rolling coal–the operation of the furnace being just as regular with fine coal, even that sifted through screens of 0.02 meter.

The second class of advantages naturally results from the almost complete prevention of access of cold air. The saving in wastage amounts to 3 or 4 per cent., that is to say, 100 kilogrammes of iron produced is accompanied by a loss of only 9 to 10 kilogrammes, instead of 13 to 15 as ordinarily reckoned.

The diminution in the cost of repairs is due to the fact that the furnace doors, of which there are two, permit of easy access to all parts of the sole; moreover, the coal never coming in contact with the fire-bridges, the latter last much longer than those in other styles of furnaces, and can be used for several weeks without the necessity of the least repair. The reduced wear of the grates results from the low temperature that can be used in the furnace, and the quantity of clinker that can be left therein without interfering with its operation, thus permitting of having the grates always black. These latter in no wise change, and after five months of work the square bars still preserve their sharpness of edges.

As for the improvements in the conditions of the work of puddling, it may be stated that with a uniform price per 100 kilogrammes for all the furnaces, the laborers working at the gas furnaces can earn 25 to 30 per cent. more than those working at ordinary furnaces.

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GESSNER’S CONTINUOUS CLOTH-PRESSING MACHINE.

It is well known that there are several serious drawbacks in the usual plan of pressing woolen or worsted cloths and felts with press plates, press papers, and presses. Three objections of great weight may be mentioned, and events in Leeds give emphasis to a fourth. The three objections are–the labor required in setting or folding the cloth, the expense of the press papers, and the time required. The fourth objection, about which a dispute has occurred between the press-setters and the master finishers in Leeds, refers to the inapplicability of the common system to long lengths. The men object to these on account of the great labor involved in shifting the heavy mass of cloth and press plates to and from the presses. A minor drawback of this system is that it involves the presence of a fold up the middle of the piece. On account of these drawbacks it has long been understood to be desirable to expedite the process, and also to dispense with the press papers. This is the main purpose of the machine we now illustrate in section, in which the pressing is done continuously by what may be termed a species of ironing. The machine consists of a central hollow cylinder, C, three-quarters of the circumference of which is covered by the hollow boxes, M, heated by steam through the pipes shown, and which are mounted upon the levers, BB’, whose fulcra are at bb. By means of the hand-wheel, T, and worm-wheel, n, which closes or opens the levers, BB’, the pressure of the boxes upon the central roller may be adjusted at will, the spring-bolt, F, allowing a certain amount of yield. The faces of the press-boxes, MM, are covered by a curved sheet of German silver attached to the point, Y. This sheet takes the place of the press papers in the ordinary process. The course of the cloth through the machine is as follows, and is shown by the arrows: It is placed on the bottom board in front, and in its travel it passes over the rails, O, after which it is operated on by the brush, Z, leaving which it is conveyed over the rails, V and I, the rollers, K and P, and thence between the pressing roller, C, and the German silver press plate covering the heated boxes, M. Leaving these the piece passes over the roller, P, and is cuttled down in the bottom board by the cuttling motion, F, or a rolling-up motion may be applied. The maker states that arrangements for brushing and steaming may also be attached, so that in one passage through the machine a piece may be pressed, brushed, and steamed. The speed of the cylinder may be adjusted according to the quality or requirements of the goods that are under treatment. At the time of our visit, says the _Textile Manufacturer_, printed woolen pieces were being pressed at the rate of about four yards a minute, but higher speeds are often obtained. Messrs. Taylor, Wordsworth & Co., who have erected many of these machines in Leeds, Bradford, and Batley, inform us that they find they are adapted for the pressing of a wide variety of cloths, from Bradford goods and thin serges to the heavy pieces of Dewsbury and Batley. The inventor, Ernst Gessner, of Aue, Saxony, adopts an ingenious expedient for pressing goods with thick lists. He provides an arrangement for moving the cylinder endwise, according to the different widths of the pieces to be treated. One list is left outside at the end of the cylinder, and the other at the opposite end of the pressing boxes. The machine we saw was 80 in. wide on the roller, and it was one the design and construction of which undoubtedly do credit to Mr. Gessner.

[Illustration]

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IMPROVEMENTS IN WOOLEN CARDING ENGINES.

Mr. Bolette, who has made a name for himself in connection with strap dividers, has experimented in another direction on the carding engine, and as his ideas contain some points of novelty we herewith give the necessary illustrations, so that our readers can judge for themselves as to the merit of these inventions.

[Illustration: Fig. 1.]

Fig. 1 represents the feeding arrangement. Here the wool is delivered by the feed rollers, A A, in the usual manner. The longer fibers are then taken off by a comb, B, and brought forward to the stripper, E, which transfers them to the roller, H, and thence to the cylinder. The shorter fibers which are not seized by the comb fall down, but as they drop they meet a blast of air created by a fan, which throws the lighter and cleaner parts in a kind of spray upon the roller, L, whence they pass on to the cylinder, while the dirt and other heavier parts fall downwards into a box, and are by this means kept off the cylinder. It is evident that in this arrangement it is not intended to keep the long and the short fibers separate, but to utilize them all in the formation of the yarn. The arrangement shown in Fig. 2 refers to the delivery end. Instead of the sliver being wound upon the roller in the usual way, it runs upon a sheet of linen, P, as in the case of carding for felt, with a to-and-fro motion in the direction of the axis of the rollers. In this way one or more layers of the fleece can be placed on the sheet, which in that case passes backwards and forwards from roller S to R, and _vice versa_. It is, in fact, the bat arrangement used for felt, only with this difference, that the bat is at once rolled up instead of going through the bat frame. In the manufacture of felt it is of course of importance to have many very thin layers of fleece superposed over each other in order to equalize it, and if the same is applied to the manufacture of cloth it will no doubt give satisfactory results, but may be rather costly.

[Illustration: Fig. 2.]

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NOVELTIES IN RING SPINDLES.

One of the drawbacks of ring spinning is the uneven pull of the traveler, which is the more difficult to counteract as it is exerted in jerks at irregular intervals. It is argued that with spindles and bearings as usually made the spindle is supported firmly in its bearing, and cannot give in case of such a lateral pull when exerted through the yarn by the traveler, and the consequence is either a breakage of the yarn or an uneven thread. Impressed with this idea, and in order to remedy this defect, an eminent Swiss firm has hit upon the notion of driving the spindle by friction, and to make it more or less loose in the bearings, so that in case of an extra pull by the traveler the spindle can give way a little, and thus prevent the breakage of the yarn. This idea has been carried out in four different ways, and as this seems to be an entirely new departure in ring spinning, we give the illustrations of their construction in detail.

[Illustration: Fig. 1. Fig. 2. Fig. 3. Fig. 4.]

Fig. 1 represents Bourcart’s recent arrangement of attaching the thread guide to the spindle rail and the adjustable spindle. The spindle is held by the sleeve, g, which latter is screwed into the spindle rail, S, this being moved by the pinion, a; the collar is elongated upwards in a cuplike form, c, the better to hold the oil, and keep it from flying; d is the wharf, which has attached to it the sleeve, m, and which is situated loosely in the space between the spindle and the footstep, e. Above the wharf the spindle is hexagonal in shape, and to this part is attached the friction plate, a. Between the latter and the upper surface of the wharf a cloth or felt washer is inserted, to act as a brake. The footstep, e, is filled with oil, in which run the foot of the spindle and the sleeve m, the latter turning upon a steel ring situated on the bottom of the footstep. As, thus, the foot of the spindle is quite free, the upper part of the spindle can give sideways in the direction of any sudden pull, and the foot of the spindle can follow this motion in the opposite direction, the collar forming the fulcrum for the spindle. By this alteration of the vertical position of the spindle into an inclined one (though ever so trifling), the contact of the friction plate, a, and the wharf is interrupted, and thus the speed of the spindle reduced. This will cause less yarn to be wound on, and the pull thus to be neutralized; but as the wharf keeps turning at the same speed, its centrifugal force will act again upon the friction plate, and thus bring the spindle back to its vertical position as soon as the extra drag has been removed.

In Fig. 2 the footstep, e, has the foot of the spindle more closely fitting at the bottom, but the upper part of the step opens out gradually, and forms a conical cavity of a little larger diameter than the spindle, so that the latter has a considerable play sideways. The wharf carries in its lower part the sleeve, g, which runs upon a steel ring as above. The upper surface of the wharf is arched, and upon this is fitted the correspondingly arched friction plate, a, which latter is attached to the spindle by a screw. The position of the spindle is maintained by the collar, m. This collar is loose in the spindle rail, and only held by the spring, m’. If now, a lateral drag is exerted upon the upper part of the spindle, the collar car follows the direction of this drag, and the spindle thus be brought out of the vertical position, the friction plate slipping at the same time. The force of the spring conjointly with the centrifugal force will then bring back the spindle into its normal position as soon as the drag is again even.

Fig. 3 shows a spindle with a very long conical oil vessel, B, resting upon a disk, e”, in cup, e’, with a cover, e”‘. The wharf, d, is here situated high up the spindle, has the same sleeve as in the preceding case, and runs round the bush, g, upon the ring, z. The friction plate resting upon the wharf is joined to the collar, a, running out into a cup shape, which is fixed to the spindle, which here has a hexagonal form. In this case the collar gives with the spindle, which latter has the necessary play in the long footstep; and as the collar and friction-plate are one, it is brought back to its normal place by centrifugal force.

A peculiar arrangement is shown in Fig. 4. Here the ring and traveler, f, are placed as usual, but the spindle carries at the same time an inverted flier, t. The spindle turns loosely in the footstep, e, the oil chamber being carried up to the middle of its height. The wharf is placed in the same position as in the previous case, having also a sleeve running in the oil chamber, c, upon a steel ring, z. The friction-plate a, on the top of the wharf carries the flier, and on its upper surface is in contact with the inverted cup, a, which is attached to the spindle by a pin or screw. In order to limit at will the lateral motion of the spindle there is attached to the latter, between the footstep and the collar, a split ring, i, which can be closed more or less by a small set screw. The spindle is thus only held in the perpendicular position by its own velocity, which will facilitate a high degree of speed, through the entire absence of all friction in the bearings, this vertical position being assisted by the friction motion whenever the spindle has been drawn on one side. Although the notion of mounting spindles so that they can yield in order to center themselves is not new, it is evident that considerable ingenuity has been brought to bear upon the arrangement of the spindles we have described, but we are not in a position to say to what extent practice has in this case coincided with theory.–_Textile Manufacturer_.

* * * * *

PHOTO-ENGRAVING ON ZINC OR COPPER.

By LEON VIDAL.

This process is similar in many respects to the one which was some time ago communicated to the Photographic Society of France by M. Stronbinsky, of St. Petersburg, but in a much improved and complete form. An account of it was given by M. Gobert, at the meeting of the same society, on the 2d December, 1882. The following are the details, as demonstrated by me at the meeting of the 9th of May last:

Sheets of zinc or of copper of a convenient size are carefully planished and polished with powdered pumice stone. The sensitive mixture is composed of:

The whites of four fresh eggs beaten to a froth……………………. 100 parts Pure bichromate of ammonia……… 2.50 ” Water………………………… 50 “

After this mixture has been carefully filtered through a paper filter, a few drops of ammonia are added. It will keep good for some time if well corked and preserved from exposure to the light. Even two months after being prepared I have found it to be still good; but too large a quantity should not be prepared at a time, as it does not improve with keeping.

I find that the dry albumen of commerce will answer as well as the fresh. In that case I employ the following formula:

Dry albumen from eggs………….. 15 to 20 parts Water………………………… 100 ” Ammonia bichromate…………….. 2.50 “

Always add some drops of ammonia, and keep this mixture in a well corked bottle and in a dark place.

To coat the metal plate, place it on a turning table, to which it is made fast at the center by a pneumatic holder; to assure the perfect adhesion of this holder, it is as well to wet the circular elastic ring of the holder before applying it to the metallic surface. When this is done, the table may be made to rotate quickly without fear of detaching the plate by the rapidity of the movement. The plate is placed in a perfectly horizontal position, where no dust can settle on it; the mixture is then poured on it, and distributed by means of a triangular piece of soft paper, so as to cover equally all the parts of the plate. Care should be taken not to flow too much liquid over the plate, and when the latter is everywhere coated, the excess is poured off into a different vessel from that which contains the filtered mixture, or else into a filter resting on that vessel. The turning table should now be inverted so that the sensitive surface may be downwards, and it is made to rotate at first slowly, afterwards more rapidly, so as to make the film, which should be very thin, quite smooth and even. The whole operation should be carried out in a subdued light, as too strong a light would render insoluble the film of bichromated albumen.

When the film is equalized the plate must be detached from the turning table and placed on a cast iron or tin plate heated to not more than 40 deg. or 50 deg. C. A gentle heat is quite sufficient to dry the albumen quickly; a greater heat would spoil it, as it would produce coagulation. So soon as the film is dry, which will be seen by the iridescent aspect it assumes, the plate is allowed to cool to the ordinary temperature, and is then at once exposed either beneath a positive, or beneath an original drawing the lines of which have been drawn in opaque ink, so as to completely prevent the luminous rays from passing through them; the light should only penetrate through the white or transparent ground of the drawing.

I say a _positive_ because I wish to obtain an engraved plate; if I wanted to have a plate for typographic printing, I should have to take a _negative_. After exposure the plate must be at once developed, which is effected by dissolving in water those parts of the bichromated gelatine which have been protected from the action of light by the dark spaces of the cliche; these parts remain soluble, while the others have been rendered completely insoluble. If the plate were dipped in clear water it would be difficult to observe the picture coming out, especially on copper. To overcome this difficulty the water must be tinged with some aniline color; aniline red or violet, which are soluble in water, answers the purpose very well. Enough of the dye must be dissolved in the water to give it a tolerably deep color. So soon as the plate is plunged into this liquid the albumen not acted on by light is dissolved, while the insoluble parts are colored by absorbing the dye, so that the metal is exposed in the lines against a red or violet ground, according to the color of the dye used.

When the drawing comes out quite perfect, and a complete copy of the original, the plate with the image on it is allowed to dry either of its own accord, or by submitting it to a gentle heat. So soon as it is dry it is etched, and this is done by means of a solution of perchloride of iron in alcohol. Both alcohol and iron perchloride will coagulate albumen; their action, therefore, on the image will not be injurious, since they will harden the remaining albumen still further. But to get the full benefit of this, the alcohol and the iron perchloride must both be free from water; it is therefore advisable to use the salt in crystals which have been thoroughly dried, and the alcohol of a strength of 95 deg..

The following is the formula:

Perchloride of iron, well dried 50 gr. Alcohol at 95 deg. 100 “

This solution must be carefully filtered so as to get rid of any deposit which may form, and must be preserved in a well-corked bottle, when it will keep for a long time. The plate is first coated with a varnish of bitumen of Judea on the edges (if those parts are not already covered with albumen) and on the back, so that the etching liquid can only act on the lines to be engraved. It is then placed, with the side to be engraved downwards, in a porcelain basin, into which a sufficient quantity of the solution of perchloride of iron is poured, and the liquid is kept stirred so as to renew the portion which touches the plate; but care must be taken not to touch with the brush the parts where there is albumen remaining. The length of time that the etching must be continued depends on the depth required to be given to the engraving; generally a quarter of an hour will be found to be sufficient. Should it be thought desirable to extend the action over half an hour, the lines will be found to have been very deeply engraved. When the etching is considered to have been pushed far enough, the plate must be withdrawn from the solution, and washed in plenty of water; it must then be forcibly rubbed with a cloth so as to remove all the albumen, and after it has been polished with a little pumice, the engraving is complete.

It will be seen that this process may be used with advantage instead of that of photo-engraving with bitumen, in cases where it is not advisable to use acids. One of my friends, Mr. Fisch, suggests the plan–which seems to deserve a careful investigation–of combining this process with that where bitumen is employed; it would be done somewhat in the following way. The plate of metal would be first coated evenly with bitumen of Judea on the turning table, and when the bitumen is quite dry, it should be again coated with albumen in the manner as described above. In full sunlight the exposure need not exceed a minute in length; then the plate would be laid in colored water, dried, and immersed in spirits of turpentine. The latter will dissolve the bitumen in all the parts where it has been exposed by the removal of the albumen not rendered insoluble by the action of light. But it remains to be seen whether the albumen will not be undermined in this method; therefore, before recommending the process, it ought to be thoroughly studied. The metal is now exposed in all the parts that have to be etched, while all the other parts are protected by a layer of bitumen coated with coagulated albumen. Hence we may employ as mordant water acidulated with 3, 4, or 5 per cent. of nitric acid, according as it is required to have the plate etched with greater or less vigor.

By following the directions above given, any one wishing to adopt the process cannot fail of obtaining good results, One of its greatest advantages is that it is within the reach of every one engaged in printing operations.–_Photo News_.

* * * * *

MERIDIAN LINE.

[Footnote: From Proceedings of the Association of County Surveyors of Ohio, Columbus, January, 1882.]

The following process has been used by the undersigned for many years. The true meridian can thus be found within one minute of arc:

_Directions_.–Nail a slat to the north side of an upper window–the higher the better. Let it be 25 feet from the ground or more. Let it project 3 feet. Kear the end suspend a plumb-bob, and have it swing in a bucket of water. A lamp set in the window will render the upper part of the string visible. Place a small table or stand about 20 feet south of the plumb-bob, and on its south edge stick the small blade of a pocket knife; place the eye close to the blade, and move the stand so as to bring the blade, string, and polar star into line. Place the table so that the star shall be seen very near the slat in the window. Let this be done half an hour before the greatest elongation of the star. Within four or five minutes after the first alignment the star will have moved to the east or west of the string. Slip the table or the knife a little to one side, and align carefully as before. After a few alignments the star will move along the string–down, if the elongation is west; up, if east. On the first of June the eastern elongation occurs about half-past two in the morning, and as daylight comes on shortly after the observation is completed, I prefer that time of year. The time of meridian passage or of the elongation can be found in almost any work on surveying. Of course the observer should choose a calm night.

In the morning the transit can be ranged with the knife blade and string, and the proper angle turned off to the left, if the elongation is east; to the right, if west.

Instead of turning off the angle, as above described, I measure 200 or 300 feet northtward, in the direction of the string, and compute the offset in feet and inches, set a stake in the ground, and drive a tack in the usual way.

Suppose the distance is 250 feet and the angle 1 deg. 40′, then the offset will be 7,271 feet, or 7 feet 31/4 inches. A minute of arc at the distance of 250 feet is seven-eighths of an inch; and this is the most accurate way, for the vernier will not mark so small a space accurately.

ANGLE OF ELONGATION.

This should be computed by the surveyor for each observation. The distance between the star and the pole is continually diminishing, and on January 1, 1882, was 1 deg. 18′ 48″.

There is a slight annual variation in the distance. July 1, 1882, it will be 1 deg. 19′ 20″. If from this latter quantity the observer will subtract 16″ for 1883, and the same quantity for each succeeding year for the next four or five years, no error so great as one-quarter of a minute will be made in the position of the meridian as determined in the summer months. If winter observations are made, the distance in January should be used. The formula for computing the angle of elongation is easily made by any one understanding spherical trigonometry, and is this:

R x sin. Polar dist.
——————— = sin. of angle of elongation. cos. lat.

As an example, suppose the time is July, 1882, and the latitude 40 deg.. Then the computation being made, the angle will be found to be 1 deg. 43′ 34″. A difference of six minutes in the latitude will make less than 10″ difference in the angle, as one can see by trial. Any good State or county map will give the latitude to within one or two miles–or minutes.

The facts being as here stated, the absurdity of the Ohio law, concerning the establishment of county meridians, becomes apparent. The longitude has nothing at all to do With the meridian; and a difference of _six miles_ in latitude makes no appreciable error in the meridian established as here suggested, whereas the statute requires the latitude within _one half a second_, which is _fifty feet_. There are some other things, besides the ways of Providence, which may be said to be “past finding out.” It is not probable that a surveyor would err so much as _three_ miles in his latitude, but should he do so, then the error in his meridian line, resulting from the mistake, will be _five seconds_, and a line _one mile_ long, run on a course 5″ out of the way, will vary but _an inch and a half_ from the true position. Surveyors well know that no such accuracy is attainable. R. W. McFARLAND,

* * * * *

ELECTRO-MANIA.

By W. MATTIEU WILLIAMS.

A history of electricity, in order to be complete, must include two distinct and very different subjects: the history of electrical science, and a history of electrical exaggerations and delusions. The progress of the first has been followed by a crop of the second from the time when Kleist, Muschenbroek, and Cuneus endeavored to bottle the supposed fluid, and in the course of these attempts stumbled upon the “Leyden jar.”

Dr. Lieberkuhn, of Berlin, describes the startling results which he obtained, or imagined, “when a nail or a piece of brass wire is put into a small apothecary’s phial and electrified.” He says that “if, while it is electrifying, I put my finger or a piece of gold which I hold in my hand to the nail, I receive a shock which stuns my arms and shoulders.” At about the same date (the middle of the last century), Muschenbroek stated, in a letter to Reaumur, that, on taking a shock from a thin glass bowl, “he felt himself struck in his arms, shoulders, and breast, so that he lost his breath, and was two days before he recovered from the effects of the blow and the terror” and that he “would not take a second shock for the kingdom of France.” From the description Of the apparatus, it is evident that this dreadful shock was no stronger than many of us have taken scores of times for fun, and have given to our school-follows when we became the proud possessors of our first electrical machine.

Conjurers, mountebanks, itinerant quacks, and other adventurers operated throughout Europe, and were found at every country fair and _fete_ displaying the wonders of the invisible agent by giving shocks and professing to cure all imaginable ailments.

Then came the discoveries of Galvani and Volta, followed by the demonstrations of Galvani’s nephew Aldini, whereby dead animals were made to display the movements of life, not only by the electricity of the Voltaic pile, but, as Aldini especially showed, by a transfer of this mysterious agency from one animal to another.

According to his experiments (that seem to be forgotten by modern electricians) the galvanometer of the period, a prepared frog, could be made to kick by connecting its nerve and muscle with muscle and nerve of a recently killed ox, with, or without metallic intervention.

Thus arose the dogma which still survives in the advertisements of electrical quacks, that “electricity is life,” and the possibility of reviving the dead was believed by many. Executed criminals were in active demand; their bodies were expeditiously transferred from the gallows or scaffold to the operating table, and their dead limbs were made to struggle and plunge, their eyeballs to roll, and their features to perpetrate the most horrible contortions by connecting nerves with one pole, and muscles with the opposite pole of a battery.

The heart was made to beat, and many men of eminence supposed that if this could be combined with artificial respiration, and kept up for awhile, the victim of the hangman might be restored, provided the neck was not broken. Curious tales were loudly whispered concerning gentle hangings and strange doings at Dr. Brookes’s, in Leicester Square, and at the Hunterian Museum, in Windmill Street, now flourishing as “The Cafe de l’Etoile.” When a child, I lived about midway between these celebrated schools of practical anatomy, and well remember the tales of horror that were recounted concerning them. When Bishop and Williams (no relation to the writer) were hanged for burking, i.e., murdering people in order to provide “subjects” for dissection, their bodies were sent to Windmill Street, and the popular notion was that, being old and faithful servants of the doctors, they were galvanized to life, and again set up in their old business.

It is amusing to read some of the treatises on medical galvanism that were published at about this period, and contrast their positive statements of cures effected and results anticipated with the position now attained by electricity as a curative agent.

Then came the brilliant discoveries of Faraday, Ampere, etc., demonstrating the relations between electricity and magnetism, and immediately following them a multitude of patents for electro-motors, and wild dreams of superseding steam-engines by magneto-electric machinery.

The following, which I copy from the _Penny Mechanic_, of June 10, 1837, is curious, and very instructive to those who think of investing in any of the electric power companies of to-day: “Mr. Thomas Davenport, a Vermont blacksmith, has discovered a mode of applying magnetic and electro-magnetic power, which we have good ground for believing will be of immense importance to the world.” This announcement is followed by reference to Professor Silliman’s _American Journal of Science and the Arts_, for April, 1837, and extracts from American papers, of which the following is a specimen: “1. We saw a small cylindrical battery, about nine inches in length, three or four in diameter, produce a magnetic power of about 300 lb., and which, therefore, we could not move with our utmost strength. 2. We saw a small wheel, five-and-a-half inches in diameter, performing more than 600 revolutions in a minute, and lift a weight of 24 lb. one foot per minute, from the power of a battery of still smaller dimensions. 3. We saw a model of a locomotive engine traveling on a circular railroad with immense velocity, and rapidly ascending an inclined plane of far greater elevation than any hitherto ascended by steam-power. And these and various other experiments which we saw, convinced us of the truth of the opinion expressed by Professors Silliman, Renwick, and others, that the power of machinery may be increased from this source beyond any assignable limit. It is computed by these learned men that a circular galvanic battery about three feet in diameter, with magnets of a proportionable surface, would produce at least a hundred horse-power; and therefore that two such batteries would be sufficient to propel ships of the largest class across the Atlantic. The only materials required to generate and continue this power for such a voyage would be a few thin sheets of copper and zinc, and a few gallons of mineral water.”

The Faure accumulator is but a very weak affair compared with this, Sir William Thomson notwithstanding. To render the date of the above fully appreciable, I may note that three months later the magazine from which it is quoted was illustrated with a picture of the London and Birmingham Railway Station displaying a first-class passenger with a box seat on the roof of the carriage, and followed by an account of the trip to Boxmoor, the first installment of the London and North-Western Railway. It tells us that, “the time of starting having arrived, the doors of the carriages are closed, and, by the assistance of the conductors, the train is moved on a short distance toward the first bridge, where it is met by an engine, which conducts it up the inclined plane as far as Chalk Farm. Between the canal and this spot stands the station-house for the engines; here, also, are fixed the engines which are to be employed in drawing the carriages up the inclined plane from Euston Square, by a rope upwards of a mile in length, the cost of which was upwards of L400.” After describing the next change of engines, in the same matter of course way as the changing of stage-coach horses, the narrative proceeds to say that “entering the tunnel from broad daylight to perfect darkness has an exceedingly novel effect.”

I make these parallel quotations for the benefit of those who imagine that electricity is making such vastly greater strides than other sources of power. I well remember making this journey to Boxmoor, and four or five years later traveling on a circular electro-magnetic railway. Comparing that electric railway with those now exhibiting, and comparing the Boxmoor trip with the present work of the London and North-Western Railway, I have no hesitation in affirming that the rate of progress in electro-locomotion during the last forty years has been far smaller than that of steam.

The leading fallacy which is urging the electro-maniacs of the present time to their ruinous investments is the idea that electro-motors are novelties, and that electric-lighting is in its infancy; while gas-lighting is regarded as an old, or mature middle-aged business, and therefore we are to expect a marvelous growth of the infant and no further progress of the adult.

These excited speculators do not appear to be aware of the fact that electric-lighting is older than gas-lighting; that Sir Humphry Davy exhibited the electric light in Albemarle Street, while London was still dimly lighted by oil-lamps, and long before gas-lighting was attempted anywhere. The lamp used by Sir Humphry Davy at the Royal Institution, at the beginning of the present century, was an arrangement of two carbon pencils, between which was formed the “electric arc” by the intensely-vivid incandescence and combustion of the particles of carbon passing between the solid carbon electrodes. The light exhibited by Davy was incomparably more brilliant than anything that has been lately shown either in London, or Paris, or at Sydenham. His arc was _four inches in length_, the carbon pencils were four inches apart, and a broad, dazzling arch of light bridged the whole space between. The modern arc lights are but pygmies, mere specks, compared with this; a leap of 1/3 or 1/4 inch constituting their maximum achievement.

Comparing the actual progress of gas and electric lighting, the gas has achieved by far the greater strides; and this is the case even when we compare very recent progress.

The improvements connected with gas-making have been steadily progressive; scarcely a year has passed from the date of Murdoch’s efforts to the present time, without some or many decided steps having been made. The progress of electric-lighting has been a series of spasmodic leaps, backward as well as forward.

As an example of stepping backward, I may refer to what the newspapers have described as the “discoveries” of Mr. Edison, or the use of an incandescent wire, or stick, or sheet of platinum, or platino-iridium; or a thread of carbon, of which the “Swan” and other modern lights are rival modifications.

As far back as 1846 I was engaged in making apparatus and experiments for the purpose of turning to practical account “King’s patent electric light,” the actual inventor of which was a young American, named Starr, who died in 1847, when about 25 years of age, a victim of overwork and disappointment in his efforts to perfect this invention and a magneto-electric machine, intended to supply the power in accordance with some of the “latest improvements” of 1881 and 1882.

I had a share in this venture, and was very enthusiastic until after I had become practically acquainted with the subject. We had no difficulty in obtaining a splendid and perfectly steady light, better than any that are shown at the Crystal Palace.

We used platinum, and alloys of platinum and iridium, abandoned them as Edison did more than thirty years later, and then tried a multitude of forms of carbon, including that which constitutes the last “discovery” of Mr. Edison, viz., burnt cane. Starr tried this on theoretical grounds, because cane being coated with silica, he predicted that by charring it we should obtain a more compact stick or thread, as the fusion of the silica would hold the carbon particles together. He finally abandoned this and all the rest in favor of the hard deposit of carbon which lines the inside of gas-retorts, some specimens of which we found to be so hard that we required a lapidary’s wheel to cut them into the thin sticks.

Our final wick was a piece of this of square section, and about 1/8 of an inch across each way. It was mounted between two forceps–one holding each end, and thus leaving a clear half-inch between. The forceps were soldered to platinum wires, one of which passed upward through the top of the barometer tube, expanded into a lamp glass at its upper part. This wire was sealed to the glass as it passed through. The lower wire passed down the middle of the tube.

The tube was filled with mercury and inverted over a cup of mercury. Being 30 inches long up to the bottom of the expanded portion, or lamp globe, the mercury fell below this and left a Torricellian vacuum there. One pole of the battery, or dynamo-machine, was connected with the mercury in the cup, and the other with the upper wire. The stick of carbon glowed brilliantly, and with perfect steadiness.

I subsequently exhibited this apparatus in the Town-hall of Birmingham, and many times at the Midland Institute. The only scientific difficulty connected with this arrangement was that due to a slight volatilization of the carbon, and its deposition as a brown film upon the lamp glass; but this difficulty is not insuperable.–_Knowledge_.

* * * * *

ACTION OF MAGNETS UPON THE VOLTAIC ARC.

The action of magnets upon the voltaic arc has been known for a long time past. Davy even succeeded in influencing the latter powerfully enough in this way to divide it, and since his time Messrs. Grove and Quet have studied the effect under different conditions. In 1859, I myself undertook numerous researches on this subject, and experimented on the induction spark of the Ruhmkorff coil, the results of these researches having been published in the last two editions of my notes on the Ruhmkorff apparatus.

[Illustration: FIG. 1]

These researches were summed up in the journal _La Lumiere Electrique_ for June 15, 1879. Recently, Mr. Pilleux has addressed to us some new experiments on the same subject, made on the voltaic arc produced by a De Meritens alternating current machine. Naturally, he has found the same phenomena that I had made known; but he thinks that these new researches are worthy of interest by reason of the nature of the arc in which he experimented, and which, according to him, is of a different nature from all those on which, up to the present time, experiments have been made. Such a distinction as this, however, merits a discussion.

With the induction spark, magnets have an action only on the aureola which accompanies the line of fire of the static discharge; and this aureola, being only a sort of sheath of heated air containing many particles of metal derived from the rheophores, represents exactly the voltaic arc.

[Illustration: FIG. 2]

Moreover, although the induced currents developed in the bobbin are alternately of opposite direction, the galvanometer shows that the currents that traverse the break are of the same direction, and that these are direct ones. The reversed currents are, then, arrested during their passage; and, in order to collect them, it becomes necessary to considerably diminish the gaseous pressure of the aeriform conductor interposed in the discharge; to increase its conductivity; or to open to the current a very resistant metallic derivation. By this latter means, I have succeeded in isolating, one from the other, in two different circuits, the direct induced currents and the reversed induced ones. As only direct currents can, in air at a normal pressure, traverse the break through which the induction spark passes, the aureola that surrounds it may be considered as being exactly in the same conditions as a voltaic arc, and, consequently, as representing an extensible conductor traversed by a current flowing in a definite direction. Such a conductor is consequently susceptible of being influenced by all the external reactions that can be exerted upon a current; only, by reason of its mobility, the conductor may possibly give way to the action exerted upon the current traversing it, and undergo deformations that are in relation with the laws of Ampere. It is in this manner that I have explained the different forms that the aureola of the induction spark assumes when it is submitted to the action of a magnet in the direction of its axial line, or in that of its equatorial line, or perpendicular to these latter, or upon the magnetic poles themselves.

Experiments of a very definite kind have not yet been made as to the nature of the arc produced by induced currents developed in alternating current machines; but, from the experiments made with electric candles, we are forced to admit that the current reacts as if it were alternately reversed through the arc, since the carbons are used up to an equal degree; and, moreover, Mr. Pilleux’s experiments show that effects analogous to those of induction coils are produced by the reaction of magnets upon the arc. There is, then, here a doubtful point that it would be interesting to clear up; and we believe that it is consequently proper to introduce in this place Mr. Pilleux’s note:

“Having at my disposal,” says he, “a powerful vertical voltaic arc of 12 centimeters in length, kept up by alternately reversed currents, and one of the most powerful permanent magnets that Mr. De Meritens employs for magneto-electric machines, I have been enabled to make the following experiments:

“1. When I caused one of the poles of my magnet to slowly approach the voltaic arc, I ascertained that, at a distance of 10 centimeters, the arc became flattened so as to assume the appearance of those gas jets called ‘butterfly.’ The plane of the ‘butterfly’ was parallel with the pole that I presented, or, in other words, with the section of the magnet. At the same time, the arc began to emit a strident noise, which became deafening when the pole of the magnet was brought to within a distance of about 2 millimeters. At this moment, the butterfly form produced by the arc was _greatly spread out, and reduced to the thickness of a sheet of paper_; and then it burst with violence, and projected to a distance a great number of particles of incandescent carbon.

“2. The magnet employed being a horseshoe one, when I directed it laterally so as to present successively, now the north and then the south pole to the arc, the ‘butterfly’ pivoted upon itself so as not to present the same surface to each pole of the magnet.”

By referring to the accompanying figure, which we extract from our note on the Ruhmkorff apparatus, it will be seen that the aureola which developed as a circular film from right to left at D, on the north pole of the magnet, N.S. (Fig. 1), projected itself in an opposite direction at C, upon the south pole, S, of the same magnet; but, between the two poles, these two contrary actions being obliged to unite, they gave rise in doing so to a very characteristic helicoid spiral whose direction depended upon that of the current of discharge through the aureola, or upon the polarity of the magnetic poles. On the contrary, when the discharge took place in the direction of the equatorial line, as in Fig. 2, the circular film developed itself in the plane of the neutral line above or below the line of discharge, according to the direction of the current and the magnetic polarity of the magnet.

There is, then, between Mr. Pilleux’s experiments and my own so great an analogy that we might draw the deduction therefrom that induced currents in alternating machines have, like those of the Ruhmkorff coil, a definite direction, which would be that of currents having the greatest tension, that is to say, that of direct currents. This hypothesis seems to us the more plausible in that Mr. J. Van Malderem has demonstrated that the attraction of solenoids with the currents, not straight, of magneto-electric machines is almost as great as that of the same solenoids with straight currents; and it is very likely that the difference which may then exist should be so much the less in proportion as the induced currents have more tension. We might, then, perhaps explain the different effects of the wear of the carbons serving as rheophores, according as the currents are continuous or alternating, by the different calorific effects produced on these carbons, and by the effects of electric conveyance which are a consequence of the passage of the current through the arc.

We know that with continuous currents the positive carbon possesses a much higher temperature than the negative, and that its wear is about twice greater than that of the latter. But such greater wear of the positive carbon is especially due to the fact that combustion is greater on it than on the negative, and also to the fact that the carbonaceous particles carried along by the current to the positive pole are deposited in part upon the other pole. Supposing that these polarities of the carbons were being constantly alternately reversed, the effects might be symmetrical from all quarters, although the only current traversing the break were of the same direction; for, admitting that the reverse currents could not traverse the break, they would exist none the less for all that, and they might give rise (as has been demonstrated by Mr. Gaugain with regard to the discharges of the induction spark intercepted by the insulating plate of a condenser) to return discharges through the generator, which would then have, in the metallic part of the circuit, the same direction as the direct currents succeeding, although they had momentarily brought about opposite polarities in the electrodes. What might make us suppose such an interpretation of the phenomenon to have its _raison d’etre_, is that with the induced currents of the Ruhmkorff coil, it is not the positive pole that is the hottest, but rather the negative; from whence we might draw the deduction that it is not so much the direction of the current that determines the calorific effect in the electrodes, as the conditions of such current with respect to the generator. I should not be surprised, then, if, in the arc formed by the alternating currents of magneto-electric machines, there should pass only one current of the same direction, and which would be the one formed by the superposition of direct currents, and if the reverse currents should cause return discharges in the midst of the generating bobbins at the moment the direct currents were generated.–_Th. Du Moncel_.

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VOLCKMAR’S SECONDARY BATTERIES.

The inventive genius of the country is now directed to these important accessories of electric enterprise, and no wonder, for as far as can at present be seen, the secret of electric motion lies in these secondary batteries. Among other contributions of this kind is the following, by Ernest Volckmar, electrician, Paris:

The object of this invention is to render unnecessary the use in secondary batteries of a porous pot which creates useless resistance to the electric current, and to store in an apparatus of comparatively small weight and bulk considerable electric force. To this end two reticulated or perforated plates of lead of similar proportions are prepared, and their interstices are filled with granules or filaments of lead, by preference chemically pure. These plates are then submitted to pressure, and placed together, with strips of nonconducting material interposed between them, in a suitable vessel containing a bath of acidulated water. The plates being connected with wires from an electric generator are brought for a while under the action of the current, to peroxidize and reduce the whole of the finely divided lead exposed to the acidulated water. The secondary battery is then complete. It will be understood that any number of these pairs of plates may be combined to form a secondary battery, their number being determined by the amount of storage required. The perforated plates of lead may be prepared by drilling, casting, or in other convenient manner, but the apertures, of whatever form, should be placed as closely together as possible, and the finely divided lead to be peroxidized is pressed into the cells or cavities so as to fill their interiors only.

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THE MINERALOGICAL LOCALITIES IN AND AROUND NEW YORK CITY, AND THE MINERALS OCCURRING THEREIN.

By NELSON H. DARTON.

There will be many persons in the city of New York and its suburbs who will not have the time or facilities for leaving town during the summer, to spend a part of their time enjoying the country, but would have sufficient time to take occasional recreation for short periods. I have sought by this paper to show a pleasurable, and at the same time very instructive use for the time of this latter class, and that is in mineralogy. In the surrounding parts of New York are many mineralogical localities, known to no others than a few professional mineralogists, etc., and from which an excellent assortment of minerals may be obtained, which would well grace a cabinet and afford considerable instruction and entertainment to their owner and friends, besides acting as an incentive to a further study of this and the other sciences. These localities which I will discuss are all within an hour’s ride from New York, and the expenses inside of a half dollar, and generally very much less. I could detail many other places further off, but will reserve that for another paper.

The course which I will pursue in my explanations I have purposely made very simple, avoiding–or when using, explaining–all technical terms. The apparatus and tests noticed are of the most rudimentary style consistent with that which is necessary to attain the simple purpose of distinguishment, and altogether I have prepared this paper for those having at the present time little or no knowledge or practice in mineralogy, while those having it can be led perhaps by the details of the localities noticed. Another reason why I have written so in detail of this last subject is, because the experiences of most amateur mineralogists are generally so very discouraging in their endeavors to find the minerals, and there is everything in giving a good start to properly fix the interest on the subject. The reason of these discouragements is simple, and generally because they do not know the portion of the locality, say, for instance, a certain township, in which the minerals occur. And if they do succeed in finding this, it is seldom that the portion in which the mineral occurs, which is generally some small inconspicuous vein or fissure, is found; and even in this it is generally difficult to recognize and isolate the mineral from the extraneous matter holding it. As an instance of this I might cite thus: Dana, in his text book on mineralogy, will mention the locality for a certain species, as Bergen Hill–say for this instance, dogtooth calespar. When we consider that Bergen Hill, in the limited sense of the expression, is ten miles long and fully one mile wide, and as the rock outcrops nearly all over it, and it is also covered with quarries, cuttings, etc., it may be seen that this direction is rather indefinite. To the professional mineralogist it is but an index, however, and he may consult the authority it is quoted from–the _American Journal of Science_, etc.–and thus find the part referred to, or by consulting other mineralogists who happen to know. Again, the person having found by inquiry that the part referred to is the Pennsylvania Railroad, and as this is fully a mile long and interspersed with various prominent looking, but veins of a mineral of little value, at any rate not the one in question, they are few who could suppose that it occurred in that. Apparently a vein of it would not be noticed at all from the surrounding rock of gravelly earth, but there it is, and in a vein of chlorite. This is so throughout the long and more or less complete stated lists of mineralogical localities. Thus I will, in describing the mineral, after explaining the conditions under which it occurs, give almost the exact spot where I have found the same mineral myself, and have left sufficiently fine specimens to carry away, and thus no time will be lost in going over fruitless ground, and further, this paper is written up to the date given at its end, insuring a necessary presence of them.

In order that one not familiar with mineral specimens should not carry off from the various localities a variety of worthless stones, etc., which are frequently more or less attractive to an inexperienced eye, the following hints may be salutary.

There are the varieties of three minerals, which are very commonly met with in greater or less abundance in mineralogical trips: they are of calcite, steatite, and quartz. They occur in so many modifications of form, color, and condition that one might speedily form a cabinet of these, if they were taken when met with, and imagine it to be of great value. The first of these is calcite. It occurs as marble, limestone; calcspar, dogtooth spar, nail head spar, stalactites, and a number of other forms, which are only valuable when occurring in perfect crystals or uniquely set upon the rock holding it. The calcspar is extremely abundant at Bergen Hill, where it might be mistaken for many of the other minerals which I describe as occurring there, and even in preference to them, to one’s great chagrin upon arriving home and testing it, to find that it is nothing but calcite. In order to avoid this and distinguish this mineral on the field, it should be tested with a single drop of acid, which on coming in contact with it bubbles up or effervesces like soda water, seidlitz powder, etc., while it does not do so with any of the minerals occurring in the same locality. This acid is prepared for use as follows: about twenty drops of muriatic acid are procured from a druggist in a half-ounce bottle, which is then filled up with water and kept tightly corked. It is applied by taking a drop out on a wisp of broom or a small minim dropper, which may be obtained at the druggist’s also. I do not say that in every case this mineral should be rejected, because it is frequently very beautiful and worthy of place in a cabinet, but should be kept only under the conditions mentioned further on in this paper, under the head of “Calcite in Weehawken Tunnel.”

The next mineral abundant in so many forms is quartz, and is not so readily distinguished as calcite. It is found of every color, shape, etc., possible, and that which is found in any of the localities I am about to describe, with the exception of fine crystals on Staten Island, are of no value and may be rejected, unless answering in detail to the description given under Staten Island. The method of distinguishing the quartz is by its hardness, which is generally so great that it cannot be scratched by the point of a knife, or at least with great difficulty, and a fragment of it will scratch glass readily; thus it is distinguished from the other minerals occurring in the localities discussed in this paper.

The other minerals so common are the varieties of steatite. This is especially so at Bergen Hill and Staten Island. They occur in amorphous masses generally, and may be distinguished by being so soft as to be readily cut by the finger nail. I will detail further upon the soapstone forms in discussing the localities on Staten Island, and the chloritic form under the head of “Weehawken Tunnel.” The surest method of avoiding these and recognizing the others by their appearance, which is generally the only guide used by a professional mineralogist, is to copy off the lists of the various minerals I describe, and, by visiting the American Museum of Natural History on any week day except Mondays and Tuesdays, one may see and become familiar with the minerals they are going in quest of, besides others in the cases. This method is much more satisfactory than printed descriptions, and saves the labor of many of the distinguishing manipulations I am about to describe, besides saving the trouble of bringing inferior specimens of the minerals home.

In going forth on a trip one should be provided with a mineralogical hammer, or one answering its purpose, and a cold chisel with which to detach or trim the minerals from adhering rocks, the bottle of acid before referred to, and a three cornered file for testing hardness, as explained further on. As I noticed before, the better plan of distinguishing a mineral is by being familiar with its appearance, but as this is generally impracticable, I will detail the modes used in lieu of this to be applied on bringing the minerals home. These distinguishments depend on difference in specific gravity, hardness, solubility in hot acids, and the action of high heat. I will explain the application of each one separately, commencing with–

_The Specific Gravity_.–In ascertaining the specific gravity the following apparatus is necessary: a small pair of hand scales with a set of weights, from one grain to one ounce. These can be procured from the apparatus maker, the scales for about fifty cents, and the weights for not much over the same amount. The scales are prepared for this work by cutting two small holes in one of the scale pans, near together, with a pointed piece of metal, and tying a piece of silk thread about eight inches long into these. In a loop at the end of this thread the mineral to be examined is suspended. It should be a pure representative of the mineral it is taken from, should weigh about from one hundred grains to an ounce, and be quite dry and free from dirt. If the piece of mineral obtained is very large, this sized portion may be often taken from it without injury; but it will not do to mar the beauty of a mineral to ascertain its specific gravity, and it is generally only applicable when a small piece is at hand. With more weights, however, a piece of a quarter pound weight may be taken if necessary. The mineral is tied into the loop and weighed, the weight being set down in the note book, either in grains or decimal parts of an ounce. Call this result A. It is then weighed in some water held in a vessel containing about a quart, taking care while weighing it that it is entirely immersed, but at the same time does not touch either the sides or bottom. Both weighings should be accurate to a grain. This result we call B. The specific gravity is found by subtracting B from A, and dividing A by the remainder. For instance, if the mineral weighed eight hundred grains when weighed in the air, and in the water six hundred, giving us the equation: 800 / (800 – 600) = sp. gr., or 4, which is the specific gravity of the mineral. If the mineral whose specific gravity is sought is an incrustation on a rock, or a mixture of a number of minerals, or would break to pieces in the water, the specific gravity is by this method of course unattainable, and other data must be used.

_The Comparative Hardness_.–The next characteristic of the mineral to be ascertained is the comparative hardness. In mineralogy there is a scale fixed for comparison, from 1 to 10, 10 being the hardest, the diamond, and Number 1 the soft soapstone. These and the intermediate minerals fixed upon the scale are generally inaccessible to those who may use the contents of this paper, and I will give some more familiar materials for comparison. 8, 9, and 10 are the topaz, sapphire, and diamond respectively, and as these and minerals of similar hardness will probably not be found in any of the localities of which I make mention, we need not become accustomed to them for the present. 7 is of sufficient hardness to scratch glass, and is also not to be cut with the file before mentioned, which is used for these determinations. 6 is of the hardness of ordinary French glass. 5 is about the hardness of horse-shoe or similar iron; 4 of the brown stone (sandstone) of which the fronts of many city buildings, etc., are built; 3 of marble; 2 of alabaster; and 1 as French chalk, or so soft as to be readily cut with the finger nail. The method of using and applying these comparisons is by having the above matters at hand, and compare them by the relative ease with which they can be cut by running the edge of the file over their surface. One will soon become familiar with the scale, and it may of course then be discarded. As it is one of the most important characteristics of some of the minerals, it should be carefully executed, and the result carefully considered. It is of course inapplicable under those conditions with minerals that are in very small crystals or in a fibrous condition.

_Action of Hot Acids_.–This very important test is never, like the above, applicable upon the field, but applied when home is reached. From the body of the mineral as pure and clean as possible a portion is chipped, about the size of a small pea; this is wrapped in a piece of stiff wrapping paper, and after placing it in contact with a solid body, crushed finally by a blow from the hammer. A pinch of the powder so obtained is taken up on the point of a penknife, and transferred into a test tube. Two or more of these should be provided, about six inches long. They may be obtained in the apparatus shop for a trifle. Some hydrochloric, or, as it is generally called, muriatic acid, is poured upon it to the depth of about three quarters of an inch; the tube is then placed in some boiling water heated over a lamp in a tinned or other vessel, and allowed to boil for from ten to fifteen minutes; the tube is then removed and its contents allowed to cool, and then examined. If the powder has all disappeared, we term the mineral “soluble;” if more or less is dissolved, “partly soluble;” if none, “insoluble;” and if the contents of the tube are of a solid transparent mass like jelly, “gelatinous;” while if transparent gelatinous flakes are left, it is so termed. As this method of distinguishment is always applicable, it is very important, and its detail and result should be carefully noticed. Care should be taken that only a small portion of the mineral is used, and also but little acid; the action should be observed, and is frequently a characteristic, in the case with calcspar, which effervesces while dissolving. The acid used is hydrochloric at first, and then, if the mineral cannot he recognized, the same treatment may be repeated using nitric acid. Both of these acids should be at hand and two ounces are generally sufficient.

_Action of Heat_.–This is, perhaps, the most important characteristic, and, when taken with the preceding data, will identify any of the minerals found in any one locality, which I will describe, from each other. The heat is applied to the mineral by means of a candle and blowpipe. A thick wax candle answers well, and an ordinary japanned tin blowpipe, costing twenty cents, will serve the purpose. The substance to be examined is held on a loop of platinum wire about one inch to the left and just below the top of the wick, which is bent toward it. Here it is steadily held, as is shown in Fig. 1, and the flame of the candle bent over upon it, and the heat intensified by blowing a steady and strong current of air across it by means of the blowpipe held in the mouth and supported by the right hand, whose elbow is resting upon the table. The current of air is difficult to keep up by one unaccustomed to the blowpipe, the skill of using which is readily obtained; it consists in breathing through the nostrils, while the air is forced out by pressure on the air held by the inflated cheeks, and not from the lungs. This can be practiced while not using the blow-pipe, and may readily be accomplished by one’s keeping his cheeks distended with air and breathing at the same time.

This heat is steadily applied until the splinter of mineral has been kept at a high red heat for a sufficient length of time to convince one of what it may do, as fuse or not, or on the edges. The first two are evident, as when it fuses it runs into a globule; the last, by inspecting it before and after the heating with a magnifying glass; sometimes it froths up when heated, and is then said to “intumesce;” or, if it flies to fragments, “decrepitates.” Upon the first it is further heated; but in the latter case, a new splinter of mineral must be broken off from the mass and heated upon the wire very cautiously until quite hot, when it may then be readily heated further without fear of loss. For holding the splinter of mineral, which should well represent the mass and be quite small, is a three-inch length of platinum wire of the thickness of a cambric-needle; this may be bought for about ten cents at the apparatus shop. The ends should be looped, as is shown in Fig. 2, and the mineral placed in the loop.

Sometimes a mineral has to be fused with borax, as I mention further on in my tables. This is done by heating the wire-loop to redness, and plunging it into some borax; what adheres is fused upon it by heating. Some more is accumulated in the same manner, until the loop is filled with a fair-sized globule. A small quantity of the mineral, which had been crushed as for the acid test, is caused to adhere to it while it is molten, and then the heat of the blast directed upon it for some time until either the small fragments of mineral dissolve, or positively refuse to do so. After cooling, the aspect of the globule is noticed as to color, transparency, etc. Care must be taken that too large an amount of the mineral is not taken, a very minute amount being sufficient.

I trust by the use of these distinguishing reactions one will be able to recognize by the tables to be given the name of the mineral in hand, especially as they are from certain parts, where all the minerals occurring therein are known to us; and I have worded the characteristics so that they will serve to isolate from all that possibly could be found in that locality.

The first general locality is Bergen Hill, New Jersey. This comprises the range of bluffs of trap rock commencing at Bergen Point and running up behind Jersey City and Hoboken, etc., to the part opposite about Thirtieth Street, New York, where it comes close to the river, and from there along the river to the north for a long distance, known as the Palisades. It is about a mile wide on an average, and from a few feet to about two hundred feet in height. The mineralogical localities in and upon it are at the following parts, commencing at the south: First Pennsylvania Railroad cuts where the mining operations are just about completed; then the Erie Tunnel, in which the specimens that first made Bergen Hill noted as a mineralogical locality, and whose equals have not since been procured, were found, but which is now inaccessible to the general public. Further north is the Morris and Essex Tunnel, in which many fine specimens were secured, and is also inaccessible; and last, but far from being least, is the Ontario Tunnel at Weehawken; and, as it is the only practicable part besides the Pennsylvania Railroad and a number of surface outcrops which I will mention, I will commence with that.

_The Weehawken Tunnel_–This tunnel is now being cut through the trap-rock for the New York, Ontario, and Western Railroad, and will be completed in a few months, but will, probably, be available as a mineralogical locality for a year to come. It is located about half a mile south of the Weehawken Ferry from Forty-second Street, New York city, and the place where to climb upon the hill to get to the shafts leading to it is made prominent by the large body of light-colored rock on the dump, a few rods north of where the east entrance is to be. The western end is in the village of New Durham, on the New Jersey Northern Railroad, and recognized by the immense earth excavations. A pass is necessary to gain admittance down the shafts, and this can be procured from the office of the company, between the third and fourth shafts to the tunnel, in the grocery and provision store just to the north of the tramway connecting the shafts on the surface. As it will not be necessary to go down in any of the shafts besides the first and second in order to fulfill the objects of this paper, no difficulty need be encountered in procuring the pass if this is stated.

These two shafts are about eight hundred feet apart and one hundred and seventy feet deep. A platform elevator is the mode of access to the tunneled portion below, and a free shower-bath is included in the descent; consequently, a rubber-coat and water tight boots are necessary. A pair of overalls should be worn if one is to engage in any active exploration below; candles should also be provided, as the electric lights, at the face of the headings, give but little light, and remind one very forcibly of a dim flash light with a foliaged tree in front of it. The electric wires for supplying these arrangements run along the north side of the tunnel for those on the east headings, and on the south side for the west. They are excellent things to keep clear of, as they have sufficient current passing through them to knock one down; thus their position can be readily ascertained.

_Modes of Occurrence of the Minerals_.–In general, the greater number of the specimens which are to be found in the tunnel occur in veins generally perpendicular, and with other minerals of little or no value, as calcite, chlorite, and imperfect crystals of the same mineral. A few occur in nodules inclosed in the solid body of rock, and in which condition they are seldom of value. The greater abundance are in the veins of the dark-green soft chlorite, and some few in horizontal beds. The minerals are found in the first condition by examining all the veins running from floor to ceiling of the tunnel. The ores of calcite first mentioned are very conspicuous, they being white in the dense black rock. They may be chipped from, as there are about thirty or forty of them exposed in each shaft, and the character of the minerals examined to see if anything but calcite is in it. This is ascertained by a drop of acid, as explained before, and by the descriptions given further on. The veins of chlorite are not so conspicuous, being of a dark-green color; but by probing along the walls with a stick or hammer, they may be recognized by their softness, or by its dull glistening appearance. They are comparatively few, but from an inch to three feet wide; and minerals are found by digging it out with a stick or a three-foot drill, to be had at the headings. Where the most minerals occur in the chlorite is when plenty of veins of calcite are in its vicinity, and its edges near the trap are dry and crumbly. It is here where the minerals are found in this crumbly chlorite, and generally in geodes–that is, the faces of the minerals all point inward, formerly a spherical mass–rough and uncouth on the outside, and from half an inch to nearly a foot in diameter. These are valuable finds, and well worth digging for. The beds of minerals generally are of but one species, and will be mentioned under the head of the minerals occurring in them. Besides, in the tunnel there are generally more or less perfect minerals upon the main dump over the edge of the bluff toward the river. Here many specimens that have escaped the eyes of the miners may be found among the loose rock, being constantly strewn out by the incline of the bed; in fact, this is the only place in which quite a number of the incident minerals may be found; but I will not linger longer on this, as I shall refer to it under the minerals individually.

The minerals occurring at the tunnel are as follows, with their descriptions and locations in the order of their greatest abundance:

_Calcite_.–This mineral occurs in great abundance in and about the tunnel, and from all the shafts. There are two forms occurring there, the most abundant of which is the rhombohedral, after Fig. 3. It can generally be obtained, however, in excellent crystals, which, although perfect in form, are opaque, but often large and beautiful. It is always packed with a thousand or its multiple of other crystals into veins of a few inches thick; and crystals are obtained by carefully breaking with edge of the cold chisel these masses down to the fundamental form shown. As the masses are never secured by the miners, they can always be picked from the piles of _debris_ around the shafts and the dumps, and afford some little instruction as to the manner in which a mineral is built up by crystallization, and may be subdivided by cleavage to a crystal of the same shape exactly, but infinitesimally small. A crystal to be worth preserving should be about an inch in diameter, and as transparent as is attainable.

Another form of calcite which is to be sparingly found is what is called dogtooth spar, having the form shown in Fig. 4. They occur in clear wine-yellow-colored crystals, from a quarter to half an inch in length; they occur in the chlorite in geodes of variable sizes, but generally two and a half inches in diameter, and which, when carefully broken in half, showed beautiful grottoes of these crystals. The few of these that I have found were in the four-foot vein of chlorite down the Shaft No. 1, to the west of the shaft about one hundred and fifty feet, and on the south wall; it may be readily found by probing for it, and then the geodes by digging in. There need be no difficulty in finding this vein if these conditions are carefully considered, or if one of the miners be asked as to the soft vein. Both these forms of calcite may be distinguished from the other minerals by first effervescing on coming in contact with the acids; second, by glowing with an intense (almost unbearably so) light when heated with the blowpipe, but not fusing. Their specific gravity is 2.6, or near it, and hardness about 3, or equal to ordinary unpolished white marble.

_Natrolite_.–The finest specimens of this mineral that have ever been found in Bergen Hill were taken from a bed of it in this tunnel, having in its original form, before it was cut out by the tunnel passing through, over one hundred square feet, and from one-half to two and a half and even three inches in thickness; it was in all possible shapes and forms–all extremely rare and beautiful. A large part of one end of this bed still remains, and, by careful cutting, fine masses may be obtained. This bed may be readily found; it is nearly horizontal, and in its center about four feet from the floor of the tunnel, and about half an inch thick. It is down Shaft No. 2, on the north wall, and commences about eighty feet from the shaft. It is cut into in some places, but there is plenty more left, and can be obtained by cutting the rock above it and easing it out by means of the blade of a knife or similar instrument. This natrolite is a grouping of very small but perfect crystals, having the forms shown in Fig. 5; they are from a quarter to an inch long, and, if not perfectly transparent, are of a pure white color; they may be readily recognized by their form, and occurring in this bed. Its hardness, which is seldom to be ascertained owing to the delicacy of the crystals, is about 5, and the specific gravity 2.2. This is readily found, but is no distinction; its reaction before the blowpipe, however, is characteristic, it readily fusing to a transparent globule, clear and glassy, and by forming a jelly when heated with acids. The bed holding the upright crystals is also natrolite in confused matted masses. This mineral has also been found in other parts of the shaft, but only in small druses. There is a prospect at present that another bed will be uncovered soon, and some more fine specimens to be easily obtained.

_Pectolite_, or as it is termed by the miners, “silky spar.”–This mineral is quite abundant and in fine masses, not of the great beauty and size of those taken from the Erie Tunnel, but still of great uniqueness. The mineral is recognized by its peculiar appearance, as is shown in Fig. 6, where it may be seen that it is in groups of fine delicate fibers about an inch long, diverging from a point into fan-shaped groups. The fibers are very tightly packed together, as are also the groups; they are very tough individually, and have a hardness of 4, and a specific gravity of about 2.5. It gelatinizes on boiling with acid, and a fragment may be readily fused in the blowpipe flame, yielding a transparent globule. The appearance is the most striking characteristic, and at once distinguishes this mineral from any of the others occurring in this locality. Considerable quantities of pectolite may generally be found on the dump, but also in Shaft No. 1, and especially No. 2. The veins of it are difficult to distinguish from the calcite, as they are almost identical in color, and many of the calcite veins are partly of pectolite–in fact, every third or fourth vein will contain more or less of it. There is, however, a very fine vein of pectolite about twenty-five feet further east from the natrolite bed; it runs from the floor to ceiling, and is about two inches in thickness; some specimens of which I took from these were unusually unique in both size and appearance. It makes a very handsome specimen for the cabinet, and should be carefully trimmed to show the characteristics of the mineral.

_Datholite_.–This mineral has been found very frequently in the tunnel, it occurring in pockets in the softer trap near the chlorite, and also in the latter, generally at a depth of one hundred and fifty feet from the surface, and consequently near the ceiling of the tunnel. All that has been found of any great beauty has been in the western end of the Shaft No. 1 and the eastern of Shaft No. 2, where the trap is quite soft; here it is found nearly every day in greater or less quantity, and from this some may generally be found on the dump, or, in the vein of chlorite which I mentioned as a locality for the dogtooth spar, considerable may be obtained in it and on its western edge near the ceiling. A ladder about thirteen feet long is used for attending the lights, and may generally be borrowed, and access to the remainder of this pocket thus gained. Datholite is also very characteristic in appearance, and can only be confounded with some forms of calcite occurring near it. It occurs in small glassy, nearly globular crystals; they are generally not over three-sixteenths of an inch in diameter, and generally pure and perfectly transparent, having a hardness of a little over 5, and specific gravity of 3; as it generally occurs as a druse upon the trap, or an apopholite, calcite, etc., this is seldom attainable, however, and we have a very distinctive characteristic in another test: this is the blowpipe, under which it at first intumesces and then fuses to a transparent globule, and the flame, after playing upon it, is of a deep green color. Nitric acid must be used to boil it up with, and with it it may be readily gelatinized. This last test will seldom be necessary, however, and may be dispensed with if the hardness and blowpipe reactions may be ascertained.

_Apopholite_.–This beautiful mineral has been found in fair abundance at times in Shafts No. 1 and 2 in pockets, and seldom in place, most of it being taken from the loose stone at the mouth of the shaft, and it may generally be found on the dump. It is readily mistaken for calcite by the miners and those unskilled in mineralogy, but a drop of acid will quickly show the difference. The sizes of the crystals are very various, from an eighth of an inch long or thick, to, in one case, an inch and a half. The colors have been varied from white to nearly all tints, including pink, purple, blue, and green; the white variety is, however, the most abundant, and makes a handsome cabinet specimen. The crystals are generally packed together in a mass, but are frequently set apart as heavy druses of crystals having the form shown in Fig. 7. Sometimes, as in the former grouping, the crystals are without the pyramidal terminations, and are then right square prisms. The fracture being at perfect right angles, distinguishes it from calcite. Its hardness is generally fully 5, the specific gravity between 2.4 and 2.5; it is difficult to fuse before the blowpipe, but is finally fused into an opaque globule. Upon heating with nitric acid it partly dissolves, and the remainder becomes flaky and gelatinous. Apopholite, although quite rare, now may be bought from the men, or at least one of the engineers of Shaft No. 2’s elevator, and generally at low terms.

_Phrenite_.–This mineral is quite abundant in Shafts No. 1 and 2, in very small masses, incrustations, and even in small crystals. It occurs embedded in or incrusting the trap, and also with calcite and apopholite. The only sure place to find it is at the southwest side of an opening through the pile of drift rock under the trestle work of the tramway, between shaft No. 1 and the dump, and within a few feet of a number of wooden vats sunk into the ground seen just before descending the hills and near the edge. Here on a number of blocks of trap it may be found, a greenish white incrustation about as thick as a knife blade; it also may be found on the main dump, and is sometimes found in plates one-eighth of an inch thick, of a darker green color, upon calcite. Its easiest distinguishment from the other minerals of this locality, with which it might be confounded, is its great hardness of from 6 to 7. It is very fragile and brittle, however, and is never perfectly transparent, but quite opaque; its specific gravity is 2.9, and it is readily fused before the blowpipe after intumescing. It partly dissolves in acid without gelatinizing, leaving a flaky residue; it is a beautiful mineral when in masses or crystals of a dark green color, but the best place in the vicinity to secure specimens of this kind is, as I will detail hereafter, at Paterson, N. J.

_Iron and Copper Pyrites_.–Both of these common but frequently beautiful minerals occur in the tunnel and adjacent rocks in great abundance. The crystals are generally about one-fourth of an inch in diameter, and groups of these may be frequently obtained on the dump in the shafts, especially No. 1 and 2, and where the rock is being cleared away for the eastern entrance to the tunnel. They resemble each other very much; the iron pyrites, however, is in cubical forms and having the great hardness of from 6 to 7, while the copper pyrites, less abundant and in forms having triangles for bases, but having sometimes other forms and a hardness of but 3 to 4. Both are similar in aspect to a piece of brass, and cannot be mistaken for any other mineral. The form of the copper pyrites is shown in Fig. 8; the iron is, as before noted, in cubes, more or less modified.

_Stilbite_.–Small quantities of this beautiful mineral have been found in Shaft No. 2, in a small bed of but a few square feet in area, but quite thick and appearing much like natrolite. This bed was about one hundred feet east from Shaft No. 2, and in the center of the heading when it was at that point. It has been encountered since in small quantities, and it would do well to look out for it in the fresh tunneled portion after the date appended to this paper. It generally occurs in the form shown in Fig. 9, grouped very similarly to natrolite, and being right upon the rock or a thin bed of itself. The crystals are generally half an inch long, but often less. The modifications of the above form, which are frequent in this species, strike one forcibly of the resemblance they bear to a broad stone spear head on a diminutive scale, with a blunted edge; their hardness is about 4, specific gravity 2.2, the color generally a pearly white or grayish. After a long boiling with nitric acid it gelatinizes, but it foams up and fuses to a transparent glass before the blowpipe. A little stilbite may often be found on the dumps.

_Laumonite_ occurs in very small quantities on calcite or apopholite, and can hardly be expected to be found on the trip; but as it might be found, I will detail some of its characteristics. Hardness 4, specific gravity 2.3; it generally occurs in small crystals, but more frequently in a crumbly, chalky mass, which it becomes upon exposure to the air. The crystals are generally transparent and frequently tinged yellow in color. It gelatinizes by boiling with acid, and after intumescing before the blowpipe, fuses to a frothy mass. To keep this mineral when in crystals from crumbling upon exposure it may be dipped in a thin mastic varnish or in a gum-arabic solution.

_Heulandite_.–This rare mineral has been found under the same conditions as laumonite in Shaft No. 2, but it is seldom to be met with, and then in small crystals. It is of a pure white color, sometimes transparent. It intumesces and readily fuses before the blowpipe, and dissolves in acid without gelatinizing. Hardness 4, specific gravity 2.2.

The few other minerals occurring in the tunnel are so extremly rare as not to be met with by any other than an expert, and it is impossible to detail the localities, as they generally occur as minute druses or incrustations upon other minerals with which they may be confounded, and have been removed as soon as discovered. The minerals referred to are analcime, chabazite, Thompsonite, and finally, the mineral which I first found in this formation, Hayesine, which is extremely rare, and of which I only obtained sufficient to cover a square inch. The particulars in regard to its locality, etc., maybe found in the _American Journal of Sciences_ for June, page 458. I will now sum up the characteristics of these several minerals of this locality in the table:

——————————————————————————- | | | | | |
Name. | H. |Sp.|Action of |Action of |Color.|Appearance. | |Gr.|Blowpipe. |hot acid. | | ———-+—–+—+—————–+—————–+——+————— | | | | | |
Calcite | 3 |2.6|Infusible, |Soluble with |White |Like Fig. | | |but glows |effervescence | |3 and 4. | | | | | |
Natrolite | 5 |2.2|Readily fused |Forms a jelly | do. |Like Fig 5. | | |to clear globule | | | | | | | | |
Pectolite | 4 |2.5| do. | do. do. | do. |Divergent | | | | | |fibers, Fig. 6. | | | | | |
Datholite | 5 |3.0|Intumesces, fused|Forms a jelly |Color-|Small, nearly | | |to clear globule,| |less |spherical, etc. | | |gives green flame| |white | | | | | | |
Apopholite| 5 |2.5|Difficult, fused |Partly soluble |Tinted|Like Fig. 7. | | |to opaque globule|in nitric acid | | | | | | | |
Phrenite | 6 |2.9|Intomesces, fused|Partly soluble |Green-|In tables and |to 7 | |to clear globule |in nitric acid, |ish |incrustations. | | | |leaving flakes | | | | | | | |
Iron | 6 |5.0|Burns and yields | |Brass |Cubical. pyrites |to 7 | |a black globule, | | | | | |decrepitates | | | | | | | | |
Copper | 3 |4.2| do. do. | | do. |Tetrahedronal. pyrites |to 4 | | | | | | | | | | |
Stilbite | 4 |2.2|Intumesces and |Difficult; jelly |White |Like Fig. 8. | | |fuses readily |on long boiling | | | | | |with nitric acid.| | | | | | | |
Laumonite | 4 |2.3|Intumesces and |Readily | do. |Generally |to 0 | |fuses to frothy |gelatinizes | |chalky. | | |mass | | |
| | | | | | Heulandite| 4 |2.2|Intumesces and |Soluble, no | do. |In right | | |readily fuses |jelly | |rhomboidal | | | | | |prisms. | | | | | |
——————————————————————————-

_To Distinguish the Minerals together the one from the other_.–Calcite by effervescing on placing a drop of acid upon it. Natrolite resembles stilbite, but may be distinguished by gelatinizing readily with hydrochloric acid and by not intumescing when heated before the blowpipe; from the other minerals by the form of the crystals and their setting, also the locality in the tunnel in which it was found.

Pectolite sometimes resembles some of the others, but may be readily distinguished by its _tough_ long fibers, not brittle like natrolite. Datholite may generally be distinguished by the form of its crystals and their glassy appearance, with great hardness, and by tingeing the flame from the blowpipe of a true green color. Apopholite is distinguished from calcite, as noticed under that species, and from the others by its form, difficult fusibility, and part solubility.

Phrenite is characterized by its hardness, greenish color, occurrence, and action of acid. Iron pyrites is always known by its brassy metallic aspect and great hardness. Copper pyrites, by its aspect from the other minerals, and from iron pyrites by its inferior hardness and less gravity.

Stilbite is characterized by its form, difficult gelatinizing, and intumescence before the blowpipe; from natrolite as mentioned under that species.

Laumonite is known by its generally chalky appearance and a probable failure in finding it.

Heulandite is distinguished from stilbite by its crystals and perfect solubility; from apopholite by form of crystals.

In the next part of this paper I will commence with Staten Island.

July 1, 1882. (_To be continued_.)

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ANTISEPTICS.

The author has endeavored to ascertain what agents are able to destroy the spores of bacilli, how they behave toward the microphytes most easily destroyed, such as the moulds, ferments, and micrococci, and if they suffice at least to arrest the development of these organisms in liquids favorable to their multiplication. His results with phenol, thymol, and salicylic acid have been unfavorable. Sulphurous acid and zinc chloride also failed to destroy all the germs of infection. Chlorine, bromine, and mercuric chloride gave the best results; solutions of mercuric chloride, nitrate, or sulphate diluted to 1 part in 1,000 destroy spores in ten minutes.–_R. Koch_.

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