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Scientific American Supplement, No. 362, December 9, 1882 by Various

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brass rod which is placed at the bottom of the burner. On turning the
cock so as to open it, a small flow of gas occurs opposite the platinum
spiral, while at the same time a rigid projecting piece affixed to the
cock bears against a small, vertical metallic piece, and brings it in
contact with the brass rod. The circuit is thus closed for an instant,
the spiral is raised to a red heat, and lights the gas, and the flame
rises and finally lights the burner. It goes without saying that on
continuing the motion the contact is broken, so as not uselessly to
waste the pile and so as to stop the escape of gas.

For gas furnaces, Mr. Loiseau is constructing a _handle-lighter_ which
is connected with the side of the furnace by flexible cords. The contact
button is on the sleeve itself, and the spiral is protected against
shocks by a metallic covering which is cleft at the extremity and the
points bent over at a right angle. All the lighters here described work
well, and are rendering valuable services. They may be considered as the
natural and indispensable auxiliaries of electric call bells, and their
use has most certainly been rendered practical through the Leclanche

* * * * *


This telephone receiver differs from its predecessors in dispensing with
an armature, the lateral vibration of the electro-magnet itself being
utilized. In previous systems in which an electro-magnet is used, the
sonorous vibrations are due either to the motion of an iron diaphragm
or armature placed close to the poles of the electro-magnet, or to the
expansion and contraction of the magnet itself. In Theiler's telephone
the electro-magnet may be of the usual U-shape, and may consist either
of soft iron or of hardened steel permanently magnetized, wound with a
suitable number of turns of insulated wire. This electro magnet is fixed
in such a manner that the vibration of either one or of both its limbs
is communicated to a diaphragm or diaphragms The patentees also employ
two or more electro-magnets in the same circuit, and utilize the
vibration of both magnets in the manner described. By attaching a light
disk or disks to the vibrating limbs, the diaphragm may be dispensed
with. Fig. 1 represents one of the telephone receivers provided with two
diaphragms or sounding boards, connected to the two limbs or cores of
the U-shaped electro-magnet by short tongues. These tongues are firmly
inserted in the diaphragms and fixed to the magnet, as shown. The poles
of the electro-magnet are brought very close together by being shaped as
shown, and the middle part of the magnet is firmly screwed to the case
of the instrument. The ends of the helix surrounding the magnet cores
may be attached as usual to two terminals, or soldered to a flexible
conductor communicating with the other parts of the telephone
apparatus. When a vibratory current is sent through the helix of the
electro-magnet, the extremities are rapidly attracted and repelled, and
this vibratory motion of the magnet cores being communicated to the
diaphragms or sounding boards, the latter are set in vibration of
varying amplitude produced by a current of varying strength, as in all
other telephones. Instead of making the electro-magnet of one continuous
piece of iron, as represented in Fig. 1, the patentees find it
more practicable to make it of the form shown in Fig. 2, where the
electro-magnet represented consists of two limbs or cores, a sole piece,
and pole extensions, the whole being screwed together, and practically
constituting one continuous piece of iron carrying the two coils. In
Fig. 2 only one of the limbs or cores of the electro-magnet is attached
to the diaphragm, the other limb being held fixed by a screw. Sometimes
the patentees hinge one of the magnet cores, or both, in the sole piece,
in which case the diaphragms or sounding boards can be made much thicker
than when the cores are rigidly fixed to the sole piece, because
the magnetic attraction of the poles has then only to overcome the
resistance of the diaphragm. Instead of using a diaphragm, they
sometimes fix a stem to one of the cores of the electro-magnet, and
mount thereon a light disk of vulcanite, wood, ivory, gutta-percha, or
any other substance which it is capable of vibrating. When using this
telephone receiver, the disk is pressed to the ear in such a manner
that its surface covers the aperture of the ear. When these telephone
receivers are used on a line of some considerable length, the patentees
prefer to magnetize the electro-magnet by a constant current from
a local battery, and to effect the variation of this constant
magnetization inductively and not directly. The electro-magnet is,
then, not inserted in the line at all, but in the primary circuit of
an induction coil, and connected with a local battery. The line is
connected to the secondry circuit of the induction coil. This device
possesses the advantage that the electro-magnet can be powerfully
magnetized with very little battery power, no matter how long the line
may be, and that steel magnets are entirely dispensed with. It is not
necessary to have a separate battery for this purpose, as the microphone
battery may also be used for the telephone receiver. The shape of the
vibrating electro-magnets is immaterial, as they may be made of a
variety of forms.--_Eng. Mechanic_.

[Illustration: FIG. 1. FIG. 2]

* * * * *



[Footnote: _La Lumiere Electrique_.]

In a lecture delivered by me on the 15th of last June in the
amphitheater of the Conservatoire des Arts et Metiers, on the
application of electricity to the production, transmission, and division
of power, I operated for the first time an electric power hammer that I
shall here describe. Its essential part is a sectional solenoid that
I have likewise made an application of in an electric motor which I
presented in July, 1830, to the Societe de Physique. Let us suppose we
superpose, one on the other, a hundred flat bobbins of a centimeter
in thickness in such a way as to form a single solenoid one meter in
height, and that the incoming and outgoing wires of each of them be
connected with the contiguous bobbins exactly in the same way as they
are in the consecutive sections or a dynamo-electric machine ring.
Finally, let us complete the resemblance by causing each junction of the
wire of one of the bobbins with the wire of its neighbor to end in a
metallic plate set into an insulating piece containing as many plates as
there are bobbins, plus one. Over this species of collector, which maybe
rectilinear or wound around a cylinder, let us pass two brushes fixed to
an insulating piece that may be moved by hand. Now, if we place these
two brushes at a distance such that the number of the plates of the
collector included between them be, for example, equal to ten, and we
give them any degree of displacement whatever, after rendering them
interdependent, the current entering through one of these brushes and
making its exit through the other will always traverse 10 bobbins.
Everything will occur, then, as if we caused the ten-bobbin solenoid to
move instead of the brushes. This granted, and the brushes being in any
position whatever, let us send a current into the apparatus, and place
therein a soft iron cylinder. By virtue of a well known law, such
cylinder will remain suspended in the interior of the solenoid, and its
longitudinal center will place itself at so much the greater distance
from that of the solenoid the more the current increases in intensity.
It would even fall entirely if the current had not an intensity above a
minimum value dependent upon many elements concerning which we have not
now to occupy ourselves. We will suppose the current intense enough to
keep the distance of the two centers much below that which would bring
about a fall of the cylinder. When such a condition is fulfilled, it is
found that if we try to remove the iron cylinder from the equilibrium
that it is in, we must apply a pressure that increases with the amount
of separation, just exactly as if it were suspended from a spring. It
results from this fact that if we displace the brushes a distance equal
to the thickness of one plate of the collector, the active solenoid will
undergo the same displacement, and its longitudinal center will move
away from that of the iron cylinder, and that the attraction exerted
upon the latter will increase. It will not be able to assume its first
value, and equilibrium cannot be re-established unless the cylinder
undergoes a displacement identical with that of the solenoid. Now,
as this latter depends upon the motion communicated to the system
of brushes, we see that, definitively, the cylinder will faithfully
reproduce the motion communicated to the brushes by the hand of
the operator. This apparatus, then, constitutes a genuine electric
servo-motor in which the current is never interrupted nor modified in
quantity or direction, no more indeed than the magnetization developed
in the soft iron cylinder. Everything takes place as if the iron
cylinder were suspended in a solenoid ten centimeters in length that
was caused to rise and fall; with the difference that the weight of the
cylinder exerts no action on the hand of the operator.


These explanations being understood, there remain but few things to be
said to cause the operation of the hammer to be thoroughly comprehended.
The elementary sections constituting the electric cylinder, A B, of the
hammer are 80 in number, and form a total length of one meter. Their
ingoing and outcoming wires end in a collector of circular form shown at
F G. The brushes are replaced by two strips, C E and C D, fixed to the
double winch, H C I, which is movable around the fixed center, C. They
can make any angle whatever with each other, so that by trial there
maybe given the active solenoid the most suitable length. When such
angle has been determined, the angle, E C D, is rendered invariable by
means of a set screw, and the apparatus is maneuvered by imparting to
the double winch, H C I, an alternating circular motion.

The iron cylinder weighs 23 kilogrammes; but, when the current has an
intensity of 43 amperes and traverses 15 sections, the stress developed
may reach 70 kilogrammes; that is to say, three times the weight of the
hammer. So this latter obeys with absolute docility the motions of the
operator's hands, as those who were present at the lecture were enabled
to see.

I will incidentally add that this power hammer was placed on a circuit
derived from one that served likewise to supply three Hefner-Alteneck
machines (Siemens D{5} model) and a Gramme machine (Breguet model P.L.).
Each of these machines was making 1,500 revolutions per minute and
developing 25 kilogrammeters per second, measured by means of a
Carpentier brake. All these apparatus were operating with absolute
independence, and had for generator the double excitation machine that
figured at the Exhibition of Electricity.

In an experiment made since then, I have succeeded in developing in each
of these four machines 50 kilogrammeters per second, whatever was the
number of those that were running; and I found it possible to add the
hammer on a derived circuit without notably affecting the operation of
the receivers.

It results from this that with my system of double excitation machine I
have been enabled to easily run with absolute independence six machines,
each giving a two-third horse-power. The economic performance, e/E,
moreover, slightly exceeded 0.50.

* * * * *


When it becomes a question of practical lighting, it is very certain
that the best electric lamp will be the one that is most simple and
requires the fewest mechanical parts. It is to such simplicity that is
due all the success of the Jablochkoff candle and the Reynier-Werdermann
lamp. Yet, in the former of these lamps, it is to be regretted that the
somewhat great and variable resistance opposed to the current in its
passage through two carbons that keep diminishing in length, in measure
as they burn, proves a cause of loss of light and of variation in it.
And it is also to be regretted that the duration of combustion of the
carbons is not longer; and, finally, it is allowable to believe that the
power employed in volatilizing the insulator placed between the carbons
is prejudicial to the economical use of this system. In order to obviate
this latter inconvenience, an endeavor has been made in the Wilde candle
to do away with the insulator, but the results obtained have scarcely
been encouraging. An endeavor has also been made to render the duration
of the carbons greater by employing quite long ones, and causing these
to move forward successively through the intermedium of a species
of rollers, or of counterpoises, as in the lamps of Mersanne and
Werdermann; but then the system becomes more complicated. Finally, in
order to keep the resistance of the carbons at a minimum and constant,
their contact with the rheophores of the circuit has been established
at a short distance from the arc, and this is one of the principal
advantages possessed by the Reynier-Werdermann system. At a certain
epoch it was thought that the problem might be simply solved by
arranging in front of each other two carbons actuated by a spiral
spring, as in car lamps, and kept at a proper distance apart for forming
the electric arc by two funnel-shaped pieces of calcined magnesia, into
which they entered like a wedge in measure as their conical point were
away through combustion. This was the system of Mr. De Baillehache,
and the trials that were made therewith were very satisfactory. But,
unfortunately, the magnesia was not able to resist very long the
temperature to which it was submitted. The problem found a better
solution in the sun-lamp but has been solved in another manner, and just
as simply, by Mr. Solignac, and the results obtained by him have been
very satisfactory as regarded from the standpoint of steadiness of the
luminous point.

In this system, a general view of which is given in Fig. 1, and the
arrangement in Figs. 2 and 3, the carbons, F F, which are horizontal and
about fifty centimeters in length, are thrust toward each other by
two barrels, K, K, which wind up two chains, E, E, passing around the
pulleys, D, D, fitted to the extremities of the carbons. These latter
are provided beneath with small glass rods, G, G, whose extremities
toward the arc abut at a short distance from the latter against a nickel
stop, L (Fig. 3), which supports them, moreover, at M, by means of
a tappet whose position is regulated by a screw. The current is
transmitted to the carbons by two friction rollers, I, I, which serve at
the same time as a guide for them, and which give the electric flux a
passage of only one or two centimeters over the front of the carbon
to form the arc. Finally, the whole is held by a support, A, and two
pieces, CB, CB, which at the same time lead the current to the friction
rollers through projections, J. The two systems are made to approach
or recede from each other, in order to form the arc, by means of a
regulating screw, H.

At present, the lighting of these lamps is effected by means of this
screw, H, but Mr. Solignac is now constructing a model in which the
lighting will be performed automatically by means of a solenoid that
will react upon a carbon lighter, as in several already well known

[Illustration: Fig. 1]

If the preceding description has been well-understood, it will be seen
that the carbons are arrested in their movement toward each other only
by the glass rods, G, abutting against L; but, as the stops, L, are not
far from the arc, and as the heat to which they are exposed is so much
the greater in proportion as the incandescent part of the carbons is
nearer them, it results that for a certain elongation of the arc the
temperature becomes sufficient to soften the glass of the rods, G, G,
so that they bend as shown at O (Fig. 3), and allow the carbons to move
onward until the heat has sufficiently diminished to prevent any further
softening of the glass. In measure as the wearing away progresses, the
preceding effects are reproduced; and, as these are produced in an
imperceptible and continuous manner, there is perceived no jumping nor
inconstancy in the light of the arc. Under such conditions, then, the
regulation of the arc is effected under the very influence of the
effect produced; and not under that of an action of a different nature
(electro-magnetism), as happens in other regulators. It is certain that
this idea is new and original, and the results that we have witnessed
from it have been very satisfactory. There is but one regulation to
perform, and that at the beginning, but this once done the apparatus
operates with certainty, and for a long time. With a Meritens machine of
the first model it has been found possible to light five lamps of this
kind placed in the same circuit.

[Illustration: Fig. 2]

According to the inventor, this lamp will give a light of 100 carcels
per one horse-power, and with a three horse-power six lamps may be
lighted; but we have made no experiments to ascertain the correctness of
these figures.

As for the cost of the glass rods, that amounts to one franc per
two hundred meters length. They can, then, be considered only as an
insignificant expense in the cost of the carbons. We consequently
believe that it will be possible to employ this system advantageously in
practice.--_Th. du Moncel_.

[Illustration: Fig. 3]

* * * * *


Since the month of May last, the concert at the Champs Elysees has been
lighted by sixteen voltaic arc lamps on a new and very simple system,
which gives excellent results in the installation under consideration.
The sixteen lamps are on the divisible system, and their regulation is
based upon the principle of derivation. They are supplied by a Siemens
alternating current machine and arranged in four circuits, on each of
which are mounted four lamps in series. The accompanying figures will
allow the reader to readily understand the system, which is as simple
as it is ingenious, and which has been combined by Mr. Mondos so as to
obtain a continuous and independent regulation of each lamp.

In this system the lower carbon is stationary, the luminous point
descending in measure as the carbons wear away through combustion. The
upper carbon descends by its own weight, and imperceptibly, so as to
keep the arc at its normal length.

The mechanism that controls the motions of the upper rod that supports
the carbon-holder consists of two bobbins of fine wire, E (Fig. 2),
mounted on a derived circuit on the terminals of the lamp; of a lever,
L, articulated at O, and supporting a tube, TT', and the whole movable
part balanced by a counterpoise, P. This lever, P, carries two soft iron
cores, F, which enter the bobbins, E, and become magnetized under the
influence of the current that passes through them. The upper part of
the tube, T, carries a square upon which is articulated at O' a second
lever, L', balanced by a second counterpoise, P', and carrying a flat
armature, _p_, opposite the cores, F', that are fixed to the first
horizontal lever, L. The carbon-holder rod, CC', slides freely in the
tube, TT', and is wedged therein by a small piece, _a m l_, fixed to
the lever, L'. For this reason the tube, TT', is provided with a notch
opposite the piece _a m l_, and the two arms, _a_ and _m_, of the latter
are shaped like a V, as may be seen in part in the plan in Fig. 2. It is
now easy to understand how the system operates; when the current is not
traversing the circuit, the carbons are separated; but, at the moment
the circuit is closed for lighting a series of lamps, it traverses the
electro-magnet, which then becomes very powerful, and draws down the
cores, F, along with the lever, L, the tube, TT', and the carbon-holder,
CC', and brings the carbons in contact. The arc then forms, and the
current divides between the arc and the bobbins, E. Its action upon the
cores, F, becomes weak, and it can no longer balance the counterpoise,
P, which falls back, and raises the system again. The arc thus
becomes _primed_. The cores, F, however, preserve a certain amount of
magnetization; the armature, _p_, is attracted, and the lever, L',
assumes a position of equilibrium such that the piece, _a m l_, wedges
the rod, CC', in the tube, TT', and holds it suspended. When, through
wear of the carbons, the arc elongates, a greater portion of the current
passes into the bobbins, E, the armature, _p_, is attracted with more
force, and the lever, L', swings around the point, O'. The rotation of
L' separates the piece, _a m l_, from the rod, CC', which, being thus
set free, slides by its own weight and shortens the arc. The current
then becomes weak in E, the armature, _p_, is not so strongly attracted,
the lever, L', pivots slightly around O' under the action of the weight,
P', and the brake or wedge enters the notch anew, and stops the descent
of the carbon. In practice, the motions that we have just described are
exceedingly slight; the carbon moves imperceptibly, and the length of
the arc remains invariable.

[Illustration: Fig. 1--MONDOS'S ELECTRIC LAMP.]

It will be seen, then, that the lever, L, and the tube, TT', serve
exclusively for _lighting_, and the lever, L', exclusively for
regulating the distance of the carbons.

This lamp exhibits great elasticity, and can operate, without a
change of any part of its mechanism, with currents of very different
intensities. It suffices for obtaining a proper working of the apparatus
in each case, to regulate the distance from the weight, P', to the point
of suspension, O', and the distance from the armature, _p_, to the
cores, F. At the Champs Elysees concerts the lamps are operating with
alternating currents; but they are capable of operating with continuous
ones also, although the slight tremor of the electro-magnetic system,
due to the use of alternating currents and as a consequence of rapid
changes of magnetization, seems in principle very favorable to systems
in which the descent of the carbon is based upon friction instead of a
clutch. At the Champs Elysees concerts the lamps burn crayons of 9 to
10 millimeters with a current of 9 to 10 amperes and an effective
electro-motive power of 60 volts per lamp. The light is very steady,
and the effect produced is most satisfactory. The dispensing with all
clock-work movement and regulating springs makes this electric lamp
of Mr. Mondos a simple and plain apparatus, capable of numerous
applications in the industries, in wide, open spaces, in all cases where
foci of medium intensity have to be employed, and where it is desired to
arrange several lamps in the same circuit.--_La Nature_.

[Illustration: Fig. 2--REGULATING MECHANISM.]

* * * * *



Aluminum is a shining, white, sonorous metal, having a shade between
silver and platinum. It is a very light metal, being lighter than glass
and only about one-fourth as heavy as silver of the same bulk. It is
very malleable and ductile, and is remarkable for its resistance to
oxidation, being unaffected by moist or dry air, or by hot or cold
water. Sulphureted hydrogen gas, which so readily tarnishes silver,
forming a black film on the surface, has no action on this metal.

Next to silica, the oxide of aluminum (alumina) forms, in combination,
the most abundant constituent of the crust of the earth (hydrated
silicate of alumina, clay).

Common alum is sulphate of alumina combined with another sulphate, as
potash, soda, etc. It is much used as a mordant in dyeing and calico
printing, also in tanning.

Aluminum is of great value in mechanical dentistry, as, in addition
to its lightness and strength, it is not affected by the presence of
sulphur in the food--as by eggs, for instance.

Dr. Fowler, of Yarmouthport, Mass., obtained patents for its combination
with vulcanite as applied to dentistry and other uses. It resists
sulphur in the process of vulcanization in a manner which renders it an
efficient and economical substitute for platinum or gold.

Aluminum is derived from the oxide alumina, which is the principal
constituent of common clay. Lavoissier, a celebrated French chemist,
first suggested the existence of the metallic bases of the earths and
alkalies, which fact was demonstrated twenty years thereafter by
Sir Humphry Davy, by eliminating potassium and sodium from their
combinations; and afterward by the discovery of the metallic bases of
baryta, strontium, and lime. The earth alumina resisting the action of
the voltaic pile and the other agents then used to induce decomposition,
twenty years more passed before the chloride was obtained by Oerstadt,
by subjecting alumina to the action of potassium in a crucible heated
over a spirit lamp. The discovery of aluminum was at last made by Wohler
in 1827, who succeeded in 1846 in obtaining minute globules or beads
of this metal by heating a mixture of chloride of alumina and sodium.
Deville afterward conducted some experiments in obtaining this metal at
the expense of Napoleon III., who subscribed L1,500, and was rewarded by
the presentation of two bars of aluminum. The process of manufacture was
afterward so simplified that in 1857 its price at Paris was about two
dollars an ounce. It was at first manufactured from common clay, which
contains about one-fourth its weight of aluminum, but in 1855 Rose
announced to the scientific world that it could be obtained from a
material called "cryolite," found in Greenland in large quantities,
imported into Germany under the name of "mineral soda," and used as a
washing soda and in the manufacture of soap. It consists of a double
fluoride of aluminum, and only requires to be mixed with an excess of
sodium and heated, when the mineral aluminum at once separates. Its cost
of manufacture is given in this estimate for one pound of metal: 16 lb.
of cryolite at 8 cents per pound, $1.28: 21/2 lb. metallic sodium at about
26 cents per pound, 70 cents; flux and cost of reduction, $2.02; total,

Aluminum is used largely in the manufacture of cheap jewelry by making a
hard, gold-colored alloy with copper, called aluminum bronze, consisting
of 90 per cent. of copper and 10 per cent. of aluminum. Like iron, it
does not amalgamate directly with mercury, nor is it readily alloyed
with lead, but many alloys with other metals, as copper, iron, gold,
etc., have been made with it and found to be valuable combinations.
One part of it to 100 parts of gold gives a hard, malleable alloy of
a greenish gold color, and an alloy of 3/4 iron and 1/4 aluminum does not
oxidize when exposed to a moist atmosphere. It has also been used to
form a metallic coating upon other metals, as copper, brass, and German
silver, by the electro-galvanic process. Copper has also been deposited,
by the same process, upon aluminum plates to facilitate their being
rolled very thin; for unless the metal be pure, it requires to be
annealed at each passage through the rolls, and it is found that its
flexibility is greatly increased by rolling. To avoid the bluish white
appearance, like zinc, Dr. Stevenson McAdam recommends immersing the
article made from aluminum in a heated solution of potash, which will
give a beautiful white frosted appearance, like that of frosted silver.

F.W. Gerhard obtained a patent in 1856, in England, for an improved
means of obtaining aluminum metal, and the adaptation thereof to the
manufacture of certain useful articles. Powdered fluoride of aluminum is
placed alone or in combination with other fluorides in a closed furnace,
heated to a red heat, and exposed to the action of hydrogen gas, which
is used as a reagent in the place of sodium. A reverberating furnace is
used by preference. The fluoride of aluminum is placed in shallow trays
or dishes, each dish being surrounded by clean iron filings placed in
suitable receptacles; dry hydrogen gas is forced in, and suitable entry
and exit pipes and stop-cocks are provided. The hydrogen gas, combining
with the fluoride, "forms hydrofluoric acid, which is taken up by the
iron and is thereby converted into fluoride of iron." The resulting
aluminum "remains in a metallic state in the bottom of the trays
containing the fluoride," and may be used for a variety of manufacturing
and ornamental purposes.

The most important alloy of aluminum is composed of aluminum 10, copper
90. It possesses a pale gold color, a hardness surpassing that of
bronze, and is susceptible of taking a fine polish. This alloy has found
a ready market, and, if less costly, would replace red and yellow brass.
Its hardness and tenacity render it peculiarly adapted for journals and
bearings. Its tensile strength is 100,000 lb., and when drawn into wire,
128,000 lb., and its elasticity is one-half that of wrought iron.

General Morin believes this alloy to be a perfect chemical combination,
as it exhibits, unlike the gun metal, a most complete homogeneousness,
its preparation being also attended by a great development of heat, not
seen in the manufacture of most other alloys. The specific gravity of
this alloy is 7.7. It is malleable and ductile, may be forged cold as
well as hot, but is not susceptible of rolling; it may, however, be
drawn into tubes. It is extremely tough and fibrous.

Aluminum bronze, when exposed to the air, tarnishes less quickly than
either silver, brass, or common bronze, and less, of course, than iron
or steel. The contact of fatty matters or the juice of fruits does not
result in the production of any soluble metallic salt, an immunity which
highly recommends it for various articles for table use.

The uses to which aluminum bronze is applicable are various. Spoons,
forks, knives, candle-sticks, locks, knobs, door-handles, window
fastenings, harness trimmings, and pistols are made from it; also
objects of art, such as busts, statuettes, vases, and groups. In France,
aluminum bronze is used for the eagles or military standards, for armor,
for the works of watches, as also watch chains and ornaments. For
certain parts, such as journals of engines, lathe-head boxes, pinions,
and running gear, it has proved itself superior to all other metals.

Hulot, director of the Imperial postage stamp manufactory in Paris, uses
it in the construction of a punching machine. It is well known that the
best edges of tempered steel become very generally blunted by paper.
This is even more the case when the paper is coated with a solution of
gum arabic and then dried, as in the instance of postage stamp sheets.
The sheets are punched by a machine the upper part of which moves
vertically and is armed with 300 needles of tempered steel, sharpened in
a right angle. At every blow of the machine they pass through the
holes in the lower fixed piece, which correspond with the needles, and
perforate five sheets at every blow. Hulot now substitutes this piece by
aluminum bronze. Each machine makes daily 120,000 blows, or 180,000,000
perforations, and it has been found that a cushion of the aluminum alloy
was unaffected after some months' use, while one of brass is useless
after one day.

Various formulae are given for the production of alloys of aluminum, but
they are too numerous and intricate to enter into here.

* * * * *



The method generally adopted for the determination of potassa in
manures, i. e., the direct incineration of the sample, may in certain
cases occasion considerable errors in consequence of the volatilization
of a portion of the potassium products.

To avoid this inconvenience, the author proposes a preliminary treatment
of the manure with sulphuric acid at 1.845 sp. gr., to convert potassium
nitrate and chloride into the fixed sulphate. The sulphuric acid attacks
the manure energetically, and much facilitates the incineration, which
may be effected at a dark red heat. The ignited portion (10 grms.) is
exhausted with boiling distilled water acidulated with hydrochloric
acid, and the filtrate, when cold, is made up to 500 c. c. Of this
solution 50 c c., representing 1 grm. of the sample, are taken, and,
after being heated until close upon ebullition, baryta-water is added
until a strong alkaline reaction is obtained. The sulphuric and
phosphoric acids, alumina, magnesia, etc, are thus precipitated. The
filtrate is heated to a boil, and mixed with ammonia and ammonium
carbonate, to precipitate the excess of baryta in solution. The last
traces of lime are eliminated by means of a few drops of ammonium
oxalate. The filtrate is evaporated down on the water-bath, and the
ammoniacal salts are expelled by carefully raising the temperature to
dull redness. After having taken up the residue in distilled water it
is treated with platinum chloride, and the potassium chloro-platinate
obtained is reduced with oxalic acid. The quantity of potassa present
in the manure can be calculated from the weight of platinum
obtained.--_Bull. de la Soc. Chim. de Paris_.

* * * * *


[Footnote: Read before the New York Academy of Sciences, February 6,


What are called the carbon minerals--peat, lignite, coal, graphite,
asphalt, petroleum, etc.--are, properly speaking, not minerals at
all, as they are organic substances, and have no definite chemical
composition or crystalline forms. They are, in fact, chiefly the
products or phases of a progressive and inevitable change in
plant-tissue, which, like all organic matter, is an unstable compound
and destined to decomposition.

In virtue of a mysterious and inscrutable force which resides in the
microscopic embryo of the seed, a tree begins its growth. For a brief
interval, this growth is maintained by the prepared food stored in the
cotyledons, and this suffices to produce and to bring into functional
activity--some root-fibrils below and leaves above, with which
the independent and self-sustained life of the individual begins.
Henceforward, perhaps for a thousand years, this life goes on, active in
summer and dormant in winter, absorbing the sunlight as a motive power
which it controls and guides. Its instruments are the discriminating
cells at the extremities of the root-fibrils, which search for, select,
and absorb the crude aliment adapted to the needs of the plant to which
they belong, and the chlorophyl cells--the lungs and stomach of the
tree--in the leaves. During all the years of the growth of the plant,
these organs are mainly occupied in breaking the strongly riveted bonds
that unite oxygen and carbon in carbonic acid; appropriating the carbon
and driving off most of the oxygen. In the end, if the tree is, e. g.,
a _Sequoia_, some hundreds of tons of solid, organized tissue have been
raised into a column hundreds of feet in height, in opposition to the
force of gravitation and to the affinities of inorganic chemistry.

The time comes, however, sooner or later, when the power which has
created and the life that has pervaded this wonderful structure
abandon it. The affinities of inorganic chemistry immediately reassert
themselves, in ordinary circumstances rapidly tearing down the ephemeral

The disintegration of organic tissue, when deserted by the force which
has animated and preserved it, gives rise to the phenomena which form
the theme of this paper.

Most animal-tissue decomposes with great rapidity, and plant tissue,
when not protected, soon decays. This decay is essentially oxidation,
since its final result is the restoration to the atmosphere of carbonic
acid, which is broken up in plant-growth by the appropriation of its
carbon. Hence it is a kind of combustion, although this term is more
generally applied to very rapid oxidation, with the evolution of
sensible light and heat. But, whether the process goes on rapidly or
slowly, the same force is evolved that is absorbed in the growth of
plant-tissue; and by accelerating and guiding its evolution, we are able
to utilize this force in the production at will of heat, light, and
their correlatives, chemical affinity, motive power, electricity, and
magnetism. The decomposition of plants may, however, be more or less
retarded, and it then takes the form of a destructive distillation,
the constituents reacting upon each other, and forming temporary
combinations, part of which are evolved, and part remain behind. Water
is the great extinguisher of this as of the more rapid oxidation that we
call combustion; and the decomposition of plant-tissue under water is
extremely slow, from the partial exclusion of oxygen. Buried under thick
and nearly impervious masses of clay, where the exclusion of oxygen is
still more nearly complete, the decomposition is so far retarded that
plant-tissue, which is destroyed by combustion almost instantaneously,
and if exposed to "the elements"--moisture with a free access of
oxygen--decays in a year or two, may be but partially consumed when
millions of years have passed. The final result is, however, inevitable,
and always the same, viz., the oxidation and escape of the organic
mutter, and the concentration of the inorganic matter woven into its
composition--in it, but not of it--forming what we call the ash of the

Since the decomposition of organic matter commences the instant it is
abandoned by the creative and conservative vital force, and proceeds
uninterruptedly, whether slowly or rapidly, to the final result, it is
evident that each moment in the progress of this decomposition presents
us with a phase of structure and composition different from that which
preceded and from that which follows it. Hence the succession of these
phases forms a complete sliding scale, which is graphically shown in
the following diagram, where the organic constituents of plant
tissue--carbon, hydrogen, oxygen, and nitrogen--appear gradually
diminishing to extinction, while the ash remains nearly constant, but
relatively increasing, till it is the sole representative of the fabric.


We may cut this triangle of residual products where we please, and by
careful analysis determine accurately the chemical composition of a
section at this point, and we may please ourselves with the illusion, as
many chemists have done, that the definite proportions found represent
the formula of a specific compound; but an adjacent section above or
below would show a different composition, and so in the entire triangle
we should find an infinite series of formulae, or rather no constant
formulae at all. We should also find that the slice, taken at any point
while lying in the laboratory or undergoing chemical treatment, would
change in composition, and become a different substance.

In the same way we can snatch a brand from the fire at any stage of its
decomposition, or analyze a decaying tree trunk during any month of its
existence, and thus manufacture as many chemical formulae as we like,
and give them specific names; but it is evident that this is child's
play, not science. The truth is, the slowly decomposing tissue of the
plants of past ages has given us a series of phases which we have
grouped under distinct names, and we have called one group peat, one
lignite, another coal, another anthracite, and another graphite. We have
spaced off the scale, and called all within certain lines by a common
name; but this does not give us a common composition for all the
material within these lines. Hence we see that any effort to define or
describe coal, lignite, or anthracite accurately must be a failure,
because neither has a fixed composition, neither is a distinct
substance, but simply a conventional group of substances which form part
of an infinite and indivisible series.

But this sliding scale of solid compounds, which we designate by
the names given above, is not the only product of the natural and
spontaneous distillation of plant tissue. Part of the original organic
mass remains, though constantly wasting, to represent it; another part
escapes, either completely oxidized as carbonic acid and water, or in
a volatile or liquid form, still retaining its organic character, and
destined to future oxidation, known as carbureted hydrogen, olefiant
gas, petroleum, etc.

Hence, in the decomposition of vegetable tissue, two classes of
resultant compounds are formed, one residual and the other evolved; and
the genesis and relation of the carbon minerals may be accurately shown
by the following diagram:

_Residual Products_ | _Evolved Products_
Peat. }
| }
Lignite. }
| } { Carbonic Acid.
Bitumious Coal. } { Carbonic Oxide.
| } { Carbureted Hydrogen, etc.
Semi-bitumious " } { Water.
| } { {Maltha.
Anthracite. } { { |
| } { {Asphalt etc.
Graphitie Anthracite. } { Petro- { |
| } { leum {Asphaltic Coal.
Graphite. } { |
| } {Asphaltic Anthracite.
Ash. } { |
{ " Graphite.

[NOTE.--In this diagram, the vertical line connecting the names of the
residual products (and of the derivatives of petroleum) indicates that
each succeeding one is produced by further alteration from that which
precedes it, and not independently. Also, the arrangement of the braces
is designed to show that any or all of the evolved products are given
off at each stage of alteration.]

The theory here proposed has not been evolved from my inner
consciousness, but has grown from careful study, through many years, of
facts in the field. A brief sketch of the evidence in favor of it is all
that we have space for here.


_Peat_.--Dry plant-tissue consists of about 50 per cent, of carbon,
44 per cent, of oxygen, with a little nitrogen, and 6 per cent. of
hydrogen. In a peat-bog, we find the upper part of the scale represented
above very well shown: plants are growing on the surface with the normal
composition of cellulose. The first stratum of peat consists of browned
and partially decomposed plant-tissue, which is found to have lost
perhaps 20 per cent. of the components of wood, and to have acquired an
increasing percentage of carbon. As we descend in the peat, it becomes
more homogeneous and darker until at the bottom of the marsh ten or
twenty feet from the surface, we have a black, carbonaceous paste,
which, when dried, resembles some varieties of coal, and approaches them
in composition. It has lost half the substance of the original plant,
and shows a marked increase in the relative proportion of carbon.

_Lignite_.--Each inch in vertical thickness of the peat-bog represents a
phase in the progressive change from wood-tissue to lignite, using
this term with its common signification to indicate, not necessarily
carbonized ligneous tissue, but plant-tissue that belongs to a past
though modern geological age--i.e., Tertiary, Cretaceous, Jurassic, or
Triassic. These lignites or modern coals are only peat beds which have
been buried for a longer or shorter time under clay, sand, or solidified
rock, and have progressed farther or less far on the road to coal. As
with peats, so with lignites, we find that at different geological
levels they exhibit different stages of this distillation--the Tertiary
lignites being usually distinguished without difficulty by the presence
of a larger quantity of combined water and oxygen, and a less quantity
of carbon, than the Cretaceous coals, and these in turn differ in the
same respects from the Triassic.

All the coals of the Tertiary and Mesozoic ages are grouped under one
name; but it is evident that they are as different from each other as
the new and spongy from the old and well-rotted peat in the peat-bog.

_Coal_.--By mere convention, we call the peat which accumulated in the
Carboniferous age by the name of bituminous coal; and an examination
of the Carboniferous strata in different countries has shown that the
peat-beds formed in the Carboniferous age, though varying somewhat, like
others, with the kind of vegetation from which they were derived, have a
common character by which they may be distinguished from the more modern
coals; containing less water, less oxygen, and more carbon, and usually
exhibiting the property of coking, which is rare in coals of later date.
Though there is great diversity in the Carboniferous coals, and it would
be absurd to express their composition by a single formula, it may be
said that, over the whole world, these coals have characteristics, as
a group, by which they can be recognized, the result of the slow
decomposition of the tissue of plants which lived in the Carboniferous
age, and which have, by a broad and general change, approximated to
a certain phase in the spontaneous distillation of plant-tissue. An
experienced geologist will not fail to refer to their proper horizon
a group of coals of Carboniferous age any more than those of the
Cretaceous or Tertiary.

_Anthracite_--In the ages anterior to the Carboniferous, the quantity
of land vegetation was apparently not sufficient to form thick and
extensive beds of peat; but the remains of plant-tissue are contained
in all the older formations, though there only as anthracite or
graphite--the last two groups of residual products. Of these we have
examples in the beds of graphite in the Laurentian rocks of Canada,
and of anthracite of the lower Silurian strata of Upper Church and
Kilnaleck, Ireland.

From these facts it is apparent that the carbon series is graded
geologically, that is, by the lapse of time during which plant-tissue
has been subjected to this natural and spontaneous distillation. But we
have better evidence than this of the derivation of one from another
of the groups of residual products which have been enumerated. In many
localities, the coals and lignites of different ages have been exposed
to local influences--such as the outbursts of trap-rock, or the
metamorphism of mountain chains--which have hastened the distillation,
and out of known earlier groups have produced the last. For example,
trap outbursts have converted Tertiary lignites in Alaska into good
bituminous coals; on Queen Charlotte's Island, on Anthracite Creek, in
southwestern Colorado, and at the Placer Mountains, near Santa Fe,
New Mexico, Cretaceous lignites into anthracite; those from Queen
Charlotte's Island and southwestern Colorado are as bright, hard, and
valuable as any from Pennsylvania. At a little distance from the focus
of volcanic action, the Cretaceous coals of southwestern Colorado have
been made bituminous and coking, while at the Placer Mountains the same
stratum may be seen in its anthracitic and lignitic stages.

A still better series, illustrating the derivation of one form of carbon
solids from another, is furnished by the coals of Ohio, Pennsylvania,
and Rhode Island. These are of the same age; in Ohio, presenting the
normal composition and physical characters of bituminous coals, that
is, of plant tissue generally and uniformly descending the scale in
the lapse of time from the Carboniferous age to the present. In the
mountains of Pennsylvania the same coal beds, somewhat affected by the
metamorphism which all the rocks of the Alleghanies have shared, have
reached the stage of _semi-bituminous_ coals, where half the volatile
constituents have been driven off; again, in the anthracite basins of
eastern Pennsylvania, the distillation further effected has formed from
these coals _anthracite_, containing only from three to ten per cent. of
volatile matter; while in the focus of metamorphic action, at Newport,
Rhode Island, the Carboniferous coals have been changed to _graphitic
anthracite_, that is, are half anthracite and half graphite. Here,
traveling from west to east, a progressive change is noted, similar to
that which may be observed in making a vertical section of a peat bog,
or in comparing the coals of Tertiary, Mesozoic, and Carboniferous age,
only the latter is the continuation and natural sequence of the former
series of changes.

In the Laurentian rocks of Canada are large accumulations of
carbonaceous matter, all of which is graphite, and that which is
universally conceded to be derived from plant-tissue. The oxidation of
graphite is artificially difficult, and in nature's laboratory slow; but
it is inevitable, as we see in the decomposition of its outcrops and the
blanching of exposed surfaces of clouded marbles, where the coloring is
graphite. Thus the end is reached, and by observations in the field,
the origin and relationship of the different carbon solids derived from
organic tissue are demonstrated.

It only remains to be said, in regard to them, that all the changes
enumerated may be imitated artificially, and that the stages of
decomposition which we have designated by the names graphite,
anthracite, coal, lignite, are not necessary results of the
decomposition of plant-tissue. A fallen tree may slowly consume away,
and all its carbonaceous matter may be oxidized and dissipated without
exhibiting the phases of lignite, coal, etc.; and lignite and coal,
when exposed to air and moisture, are burned away to ashes in the same
manner, simply because in these cases complete oxidation of the carbon
takes place, particle by particle, and the mass is not affected as a
whole in such a way as to assume the intermediate stages referred to.
Chemical analysis, however, proves that the process is essentially the
same, although the physical results are different.


The gradual wasting of plant-tissue in the formation of peat, lignite,
coal, etc., may be estimated as averaging for peat, 20 to 30 per cent.;
lignite, 30 to 50 per cent.; coal, 50 to 70 per cent.; anthracite, 70
to 80; and graphite, 90 per cent. of the original mass. The evolved
products ultimately represent the entire organic portion of the
wood--the mineral matter, or ash, being the only residuum. These evolved
products include both liquids and gases, and by subsequent changes,
solids are produced from some of them. Carbonic acid, carbonic oxide,
nitrogenous and hydrocarbon gases, water, and petroleum, are mentioned
above as the substances which escape from wood-tissue during its
decomposition. That all these are eliminated in the decay of vegetable
and animal structures is now generally conceded by chemists and
geologists, although there is a wide difference of opinion as to the
nature of the process.

It has been claimed that the evolved products enumerated above are the
results of the primary decomposition of organic matter, and never of
further changes in the residual products; i.e., that in the breaking-up
of organic tissue, variable quantities of coal, anthracite, petroleum,
marsh gas, etc., are formed, but that these are never derived, the one
from the other. This opinion is, however, certainly erroneous, and the
formation of any or all the evolved products may take place throughout
the entire progress of the decomposition. Marsh gas and carbonic acid
are seen escaping from the surface of pools where recent vegetable
matter is submerged, and they are also eliminated in the further
decomposition of peat, lignite, coal, and carbonaceous shale. Fire damp
and choke-damp, common names for the gases mentioned above, are produced
in large quantities in the mines where Tertiary or Cretaceous lignites,
or Carboniferous coals or anthracites are mined. It has been said that
these gases are simply locked up in the interstices of the carbonaceous
matter and are liberated in its excavation; but all who have worked coal
mines know that such accumulations are not sufficient to supply the
enormous and continuous flow which comes from all parts of the mass
penetrated. We have ample proof, moreover, that coal, when exposed to
the air, undergoes a kind of distillation, in which the evolution
of carbonic acid and hydrocarbon gases is a necessary and prominent

The gas makers know that if their coal is permitted to lie for months or
years after being mined, it suffers serious deterioration, yielding a
less and less quantity of illuminating gas with the lapse of time.
So coking coals are rendered dry, non-caking, and valueless for this
purpose by long exposure.

Carbureted hydrogen, olefiant gas, etc., are constant associates of the
petroleum of springs or wells, and this escape of gas and oil has been
going on in some localities, without apparent diminution, for two or
three thousand years. We can only account for the persistence of this
flow by supposing that it is maintained by the gradual distillation of
the carbonaceous masses with which such evolutions of gas or of liquid
hydro-carbons are always connected. If it were true that carbureted
hydrogen and petroleum are produced only from the primary decomposition
of organic tissue, it would be inevitable that at least the elastic
gases would have escaped long since.

Oil wells which have been nominally exhausted--that is, from which the
accumulations of centuries in rock reservoirs have been pumped--and
therefore have been abandoned, have in all cases been found to be slowly
replenished by a current and constant secretion, apparently the product
of an unceasing distillation.

In the valley of the Cumberland, about Burkesville, one of the oil
regions of the country, the gases escaping from the equivalent of the
Utica shale accumulate under the plates of impervious limestone above
until masses of rock and earth, hundreds of tons in weight, are
sometimes thrown out with great violence. Unless these gases had been
produced by comparatively recent distillation, such explosions could not

In opening a coal mine on a hillside, the first traces of the coal seam
are found in a dark stain in the superficial clay; then a substance like
rotten wood is reached, from which all the volatile constituents have
escaped. These appear, however, later, and continue to increase as the
mine is deepened, until under water or a heavy covering of rock the coal
attains its normal physical and chemical characters. Here it is evident
that the coal has undergone a long-continued distillation, which must
have resulted in the constant production of carbonic acid and carbureted

A line of perennial oil and gas springs marks the outcrop of every
great stratum of carbonaceous matter in the country. Of these, the most
considerable and remarkable are the bituminous shales of the Silurian
(Utica shale), of the Devonian (Hamilton and Huron shales), the
Carboniferous, etc. Here the carbonaceous constituent (10 to 20 per
cent.) is disseminated through a great proportion of inorganic material,
clay and sand, and seems, both from the nature of the materials which
furnished it--cellular plants and minute animal organisms--and its
dissemination, to be specially prone to spontaneous distillation. The
Utica shale is the lowest of these great sheets of carbonaceous matter,
and that supplies the hydro-carbon gases and liquids which issue from
the earth at Collingwood, Canada, and in the valley of the Cumberland.
The next carbonaceous sheet is formed by the great bituminous shale
beds of the upper Devonian, which underlie and supply the oil wells in
western Pennsylvania. In some places the shale is several hundred
feet in thickness, and contains more carbonaceous matter than all the
overlying coal strata. The outcrop of this formation, from central New
York to Tennessee, is conspicuously marked by gas springs, the flow from
which is apparently unfailing.

Petroleum is scarcely less constant in its connection with these
carbonaceous rocks than carbureted hydrogen, and it only escapes notice
from the little space it occupies. The two substances are so closely
allied that they must have a common origin, and they are, in fact,
generated simultaneously in thousands of localities.

During the oil excitement of some years since, when the whole country
was hunted over for "oil sign," in many lagoons, from which bubbles of
marsh-gas were constantly escaping, films of genuine petroleum were
found on the surface; and as the underlying strata were barren of oil,
this could only have been derived from the decaying vegetable tissue
below. In the Bay of Marquette, two or three miles north of the town,
where the shore is a peat bog underlain by Archaean rocks, I have seen
bubbles of carbureted hydrogen rising in great numbers attended by drops
of petroleum which spread as iridescent films on the surface.

The remarks which have been made in regard to the heterogeneous nature
of the solid hydrocarbons apply with scarcely less force to the gaseous
and liquid products of vegetable decomposition. The gases which escape
from marshes contain carbonic acid, a number of hydrocarbon gases (or
the materials out of which they may be composed in the process of
analysis), and finally a larger or smaller volume of nitrogenous gas.
It is possible that the elimination of these gases takes the form of
fractional distillation, and definite compounds may be formed directly
from the wood-tissue or its derivatives, and mingle as they escape. This
is, however, not certain, for the gases, as we find them, are always
mixtures and never pure. In the liquid evolved products, the petroleums,
this is emphatically true, for we combine under this name fluids which
vary greatly in both their physical and chemical characters; some are
light and ethereal, others are thick and tarry; some are transparent,
some opaque; some red, some brown, others green; some have an offensive
and others an agreeable odor; some contain asphalt in large quantity,
others paraffine, etc. Thus they form a heterogeneous assemblage of
liquid hydrocarbons, of which naphtha and maltha may be said to form
the extremes, and which have little in common, except their undefinable
name. The causes of these differences are but imperfectly understood,
but we know that they are in part dependent on the nature of the organic
material that has furnished the petroleums, and in part upon influences
affecting them after their formation. For example, the oil which
saturates the Niagara limestone at Chicago, and--which is undoubtedly
indigenous in this rock, and probably of animal origin, is black and
thick; that from Enniskillen, Canada, is also black, has a vile odor,
probably in virtue of sulphur compounds, and, we have reason to believe,
is derived from animal matter. The oils of northwestern Pennsylvania are
mostly brown, sometimes green by reflected light, and have a pungent and
characteristic odor. These are undoubtedly derived from the Hamilton
shales, which contain ten or twenty per cent, of carbonaceous matter,
apparently produced from the decomposition of sea-weeds, since these are
in places exceedingly abundant, and nearly all other fossils are absent.

The oils of Italy, though varying much in appearance, have usually an
ethereal odor that is rather agreeable; they are of Tertiary age. The
oils of Japan, differing much among themselves, have as, a common
character an odor quite different from the Pennsylvania oils. So the
petroleums of the Caspian, of India, California, etc., occurring at
different geological horizons, exhibit a diversity of physical and
chemical characters which may be fairly supposed to depend upon the
material from which they have been distilled. The oils in the same
region, however, are found to exhibit a series of differences which are
plainly the result of causes operating upon them after their production.
Near the surface, they are thicker and darker; below, and near the
carbonaceous mass from which they have been generated, they are of
lighter gravity and color. We find, in limited quantity, oils which are
nearly white and may be used in lamps without refining--which have been
refined, in fact, in Nature's laboratory. Others, that are reddish
yellow by transmitted light, sometimes green by reflected light, are
called amber oils; these also occur in small quantity, and, as I am led
to believe, have acquired their characteristics by filtration through
masses of sandstone. Whatever the variety of petroleum may be,
if exposed for a long time to the air it undergoes a spontaneous
distillation, in which gases and vapors, existing or formed, escape,
and solid residues are left. The nature of these solids varies with
the petroleums from which they come, some producing asphaltum,
others paraffine, others ozokerite, and so on through a long list of
substances, which have received distinct names as mineral species,
though rarely, if ever, possessing a definite and invariable
composition. The change of petroleum to asphalt may be witnessed at a
great number of localities. In Canada, the black asphaltic oil forms by
its evaporation great sheets of hard or tarry asphalt, called gum
beds, around the oil-springs. In the far West are numerous springs of
petroleum, which are known to the hunters as "_tar springs_," because
of the accumulations about them of the products of the evaporation and
oxidation of petroleum to tar or asphalt. Certain less common oils yield
ozokerite as a solid, and considerable accumulations of this are known
in Galicia and Utah.

Natural paraffine is less abundant, and yet in places it occurs in
considerable quantity. Asphalt is the common name for the solid residue
from the evaporation and oxidation of petroleum; and large accumulations
of this substance are known in many parts of the world, perhaps the most
noted of all being that of the "Pitch Lake". of the Island of Trinidad;
there, as everywhere else, the derivation of asphalt from petroleum is
obvious, and traceable in all stages. The asphalts, then, have a common
history in this, that they are produced by the evaporation and oxidation
of petroleum. But it should also be said that they share the diversity
of character of petroleums, and the term asphalt represents a group of
substances of which the physical characters and chemical composition
differ greatly in virtue of their derivation, and also differ from
changes which they are constantly undergoing. Thus at the Pitch Lake in
Trinidad, the central portion is a tarry petroleum, near the sides a
plastic asphalt, and finally that which is of almost rock-like solidity.
Hence we see that the solid residues from petroleum are unstable
compounds like the coals and lignites, and in virtue of their organic
nature are constantly undergoing a series of changes of which the final
term is combustion or oxidation. From these facts we might fairly infer
that asphalts formed in geological ages anterior to the present would
exhibit characters resulting from still further distillation; that they
would be harder and drier, i.e., containing less volatile ingredients
and more fixed carbon. Such is, in fact, the case; and these older
asphalts are represented by _Grahamite, Albertite_, etc., which I have
designated as asphaltic coals. These are found in fissures and cavities
in rocks of various ages, which have been more or less disturbed, and
usually in regions where springs of petroleum now exist. The Albertite
fills fissures in Carboniferous rocks in New Brunswick, on a line of
disturbance and near oil-springs. Precisely the same may be said of the
Grahamite of West Virginia. It fills a vertical fissure, which was
cut through the sandstones and shales of the coal-measures; in the
sandstones it remained open, in the shales it has been closed by the
yielding of the rock. The Grahamite fills the open fissure in the
sandstone, and was plainly introduced when in a liquid state. In the
vicinity are oil springs, and it is on an axis of disturbance. From
near Tampico, Mexico, I have received a hydrocarbon solid--essentially
Grahamite, asphalt, and petroleum. These are described as occurring near
together, and evidently represent phases of different dates in the same
substance. I have collected asphaltic coals, very similar to Grahamite
and Albertite in appearance and chemical composition, in Colorado and
Utah, where they occur with the game associates as at Tampico. I have
found at Canajoharie, New York, in cavities in the lead-veins which rut
the Utica shale, a hydrocarbon solid which must have infiltrated into
these cavities as petroleum, but which, since the remote period when the
fissures were formed, has been distilled until it is now _anthracite_.
Similar anthracitic asphalt or asphaltic anthracite is common in
the Calciferous sand-rock in Herkimer County, New York, where it is
associated with, and often contained in, the beautiful crystals of
quartz for which the locality is famous. Here the same phase of
distillation is reached as in the coke residuum of the petroleum stills.

Again, in some crystalline limestones, detached scales or crystals of
_graphite_ occur, which are undoubtedly the product of the complete
distillation of liquid hydrocarbons with which the rock was once
impregnated. The remarkable purity of such graphite is the natural
result of its mode of formation, and such cases resemble the occurrence
of graphite in cast iron and basalt. The black clouds and bands which
stain many otherwise white marbles are generally due to specks of
graphite, the residue of hydrocarbons which once saturated the rock.
Some limestones are quite black from the carbonaceous matter they
contain (Lycoming Valley, Pa., Glenn's Falls, N. Y., and Collingwood,
Canada), and these are sold as black marbles, but if exposed to heat,
such limestones are blanched by the expulsion of the contained carbon;
usually a residue of anthracite or graphite is left, forming dark spots
or streaks, as we find in the clouded and banded marbles.

Finally, the great work going on in Nature's laboratory may be closely
imitated by art; the differences in the results being simply the
consequence of differing conditions in the experiments. Vegetable tissue
has been converted artificially into the equivalents of lignite, coal,
anthracite, and graphite, with the emission of vapors, gases, and oils
closely resembling those evolved in natural processes. So petroleum may
be distilled to form asphalt, and this in turn converted into Albertite
and coke (i.e., anthracite). Grahamite has been artificially produced
from petroleum by Mr. W. P. Jenney.

In the preceding remarks, no effort has been made even to enumerate
all the so-called carbon minerals which have been described. This was
unnecessary in a discussion of the relations of the more important
groups, and would have extended this article much beyond its prescribed
length. Those who care to gain a fuller knowledge of the different
members of the various groups are referred to the admirable chapter on
the "Hydrocarbon Compounds" in Dana's Mineralogy.

It will, however, add to the value of this paper, if brief mention be
made of a few carbon minerals of which the genesis and relations are not
generally known, and in regard to which special interest is felt, such
as the diamond, jet, the hydrocarbon jellies, "Dopplerite," etc.

The diamond is found in the _debris_ of metamorphic rocks in many
countries, and is probably one of the evolved products of the
distillation of organic matter they once contained. Under peculiar
circumstances it has apparently been formed by precipitation from
sulphide of carbon or some other volatile carbon compound by elective
affinity. Laboratory experiments have proved the possibility of
producing it by such a process, but the artificial crystals are
microscopic, perhaps only because a long time is required to build up
those of larger size.

Jet is a carbonaceous solid which in most cases is a true lignite, and
generally retains more or less of the structure of wood. Masses are
sometimes found that show no structure, and these are probably formed
from bitumen which has separated from the wood of which it once formed
part, and which it generally saturates or invests. In some cases,
however, these masses of jet-like substance are plainly the residuum of
excrementitious matter voided by fishes or reptiles. These latter are
often found in the Triassic fish-beds of Connecticut and New Jersey, and
in the Cretaceous marls of the latter State.

The discovery of a quantity of hydrocarbon jelly, recently, in a
peat-bed at Scranton, Pa., has caused some wonder, but similar
substances (Dopplerite, etc.) have been met with in the peat-beds of
other countries; and while the history of the formation of this singular
group of hydrocarbons is not yet well understood, and offers an
interesting subject for future research, we have reason to believe that
these jellies have been of common occurrence among the evolved products
of the decomposition of vegetable tissue in all ages.

The fossil resins--often erroneously called gums--amber, kauri, copal,
etc., though interestingly related to the hydro-carbons enumerated on
the preceding pages, form no essential part of the series, and demand
only the briefest notice here.

_Amber_ is the resin which exuded from certain coniferous trees that,
in Tertiary times, grew abundantly in northern Europe. The leaves and
trunks of these trees have generally perished; but masses of their
resin, more enduring, buried in the earth on the shores of the Baltic,
have in the lapse of time changed physically and chemically, and have
become fitted for the ornamental purposes for which they have been used
by all civilized nations.

_Kauri_ is the resin of _Dammara australis_, a living coniferous tree of
New Zealand, and the "gum" is dug from the earth on the sites of forests
which have now disappeared.

_Copal_ is a commercial name given to the resins of several different
trees, but the most esteemed, and indeed the only true copal, is the
product of _Trachylobium Mozambicense_, a tree which grows along the
Zanzibar coast, and has left its resin buried in the sands of old raised
beaches which it has abandoned.

The diversity of character which the fossil resins exhibit shows the
complexity of the vital processes in operation in the vegetable kingdom,
and gives probability to the theory that some of the differences we find
in the carbon minerals are due to differences in the plants from which
they have been derived.

The variations in the physical and chemical characters of different
coals from the same basin, and from different parts of the same stratum,
have been sometimes credited to the same cause; but they are probably
in greater degree due to the differences in the conditions under which
these varieties have been formed.

Cannel coal, as I have shown elsewhere (_Amer. Jour. Science_, March,
1857), is completely macerated vegetable tissue which was deposited as
carbonaceous mud at the bottom of lagoons in the coal-marshes.

Caking coals were probably peat, which accumulated under somewhat
uniform conditions, was constantly saturated with moisture, and became
a comparatively homogeneous and partially gelatinous carbonaceous mass;
while the open-burning coals which show a distinctly laminated structure
and consist of layers of pitch-coal, alternating with bands of mineral
charcoal or cannel, seem to have been formed in alternating conditions,
of more or less moisture, and the bituminous portions are inclosed in
cells or are separated by partitions, so that the mass does not melt
down, but more or less perfectly holds its form when exposed to heat.

The generalities of the origin and relations of the carbon minerals
have now been briefly considered; but a review of the subject would
be incomplete without some reference to the theories which have been
advanced by others, that are in conflict with the views now presented.
There have always been some who denied the organic nature of the mineral
hydrocarbons, but it has been regarded as a sufficient answer to their
theories, that chemists and geologists are generally agreed in saying
that no instances are known of the occurrence in nature of hydrocarbons,
solid, liquid, or gaseous, in which the evidence was not satisfactory
that they had been derived from animal or vegetable tissue. A few
exceptional cases, however, in which chemists and geologists of deserved
distinction have claimed the possibility and even probability of the
production of marsh gas, petroleum, etc., through inorganic agencies,
require notice.

In a paper published in the _Annales de Chimie et de Physique_, Vol.
IX., p.481, M. Berthelot attempts to show that the formation of
petroleum and carbureted hydrogen from inorganic substances is possible,
if it be true, as suggested by Daubre, that there are vast masses of the
alkaline metals--potassium, sodium, etc.--deeply buried in the earth,
and at a high temperature, to which carbonic acid should gain access;
and he demonstrates that, these premises being granted, the formation of
hydrocarbons would necessarily follow.

But it should be said that no satisfactory evidence has ever been
offered of the existence of zones or masses of the unoxidized alkaline
metals in the earth, and it is not claimed by Berthelot that there are
any facts in the occurrence of petroleum and carbureted hydrogen in
nature which seem to exemplify the chemical action which he simply
claims is theoretically possible. Berthelot also says that, in most
cases, there can be no doubt of the organic origin of the hydrocarbons.

Mendeleeff, in the _Revue Scientifique_, 1877, p. 409, discusses at
considerable length the genesis of petroleum, and attempts to sustain
the view that it is of inorganic origin. His arguments and illustrations
are chiefly drawn from the oil wells of Pennsylvania and Canada, and
for the petroleum of these two districts he claims an inorganic origin,
because, as he says, there are no accumulations of organic matter below
the horizons at which the oils and gases occur. He then goes into a
lengthy discussion of the possible and probable source of petroleum,
where, as in the instances cited, an organic origin "is not possible."
It is a sufficient answer to M. Mendeleeff to say, that beneath the oil
bearing strata of western Pennsylvania are sheets of bituminous shale,
from one hundred to five hundred feet in thickness, which afford an
adequate, and it may be proved the true source, of the petroleum, and
that no petroleum has been found below these shales; also that the
oil-fields of Canada are all underlain by the Collingwood shales, the
equivalent of the Utica carbonaceous shales of New York, and that from
the out-crops of these shales petroleum and hydrocarbon gases are
constantly escaping. With a better knowledge of the geology of the
districts he refers to, he would have seen that the facts in the
cases he cites afford the strongest evidence of the organic origin of

Among those who are agreed as to the organic origin of the hydrocarbons,
there is yet some diversity of opinion in regard to the nature of the
process by which they have been produced.

Prof. J. P. Lesley has at various times advocated the theory that
petroleum is indigenous in the sand-rocks which hold it, and has been
derived from plants buried in them. ("Proc. Amer. Philos. Soc.," Vol.
X., pp. 33, 187, etc.)

My own observations do not sanction this view, as the limited number of
plants buried in the sandstones which are now reservoirs of petroleum
must always have borne a small proportion in volume to the mass of
inorganic matter; and some of those which are saturated with petroleum
are almost completely destitute of the impressions of plants.

In all cases where sandstones contain petroleum in quantity, I think it
will be found that there are sheets of carbonaceous matter below, from
which carbureted hydrogen and petroleum are constantly issuing. A more
probable explanation of the occurrence of petrolem in the sandstones is
that they have, from their porosity, become convenient receptacles for
that which flowed from some organic stratum below.

Dr. T. Sterry Hunt has regarded limestones, and especially the Niagara
and corniferous, as the principal sources of our petroleum; but, as I
have elsewhere suggested, no considerable flow of petroleum has ever
been obtained from the Niagara limestone, though at Chicago and Niagara
Falls it contains a large quantity of bituminous matter; also, that the
corniferous limestone which Dr. Hunt has regarded as the source of the
oil of Canada and Pennsylvania is too thin, and too barren of petroleum,
or the material out of which it is made, to justify the inference.

The corniferous limestone is never more than fifty or sixty feet thick,
and does not contain even one per cent. of hydrocarbons; and in southern
Kentucky, where oil is produced in large quantity, this limestone does
not exist.

That many limestones are more or less charged with petroleum is well
known; and in addition to those mentioned above, the Silurian limestone
at Collingwood, Canada, may be cited as an example. As I have elsewhere
shown, we have reason to believe that the petroleum here is indigenous,
and has been derived, in part, at least, from animal organisms; but the
limestones are generally compact, and if cellular, their cavities are
closed, and the amount of petroleum which, under any circumstances,
flows from or can be extracted from limestone rock is small. On the
other hand, the bituminous shales which underlie the different oil
regions afford an abundant source of supply, holding the proper
relations with the reservoirs that contain the oil, and are
spontaneously and constantly evolving gas and oil, as may be observed
in a great number of localities. For this reason, while confessing
the occurrence of petroleum and asphaltum in many limestones, I am
thoroughly convinced that little or none of the petroleum of commerce is
derived from them.

Prof. S.F. Peckham, who has studied the petroleum field of southern
California, attributes the abundant hydrocarbon emanations in that
locality to microscopic animals. It is quite possible that this is
true in this and other localities, but the bituminous shales which are
evidently the sources of the petroleum of Pennsylvania, Ohio, Kentucky,
etc., generally contain abundant impressions of sea weeds, and indeed
these are almost the only organisms which have left any traces in them.
I am inclined, therefore, now, as in my report on the rock oils of Ohio,
published in 1860, to ascribe the carbonaceous matter of the bituminous
shales of Pennsylvania and Ohio, and hence the petroleum derived from
them, to the easily decomposed cellular tissue of algae which have
in their decomposition contributed a large percentage of diffused
carbonaceous matter to the sediments accumulating at the bottom of the
water where they grew. In a recent communication to the National Academy
of Sciences, Dr. T. Sterry Hunt has proposed the theory that anthracite
is the result of the decomposition of vegetable tissue when buried in
porous strata like sandstone; but an examination of even a few of the
important deposits of anthracite in the world will show that no such
relationship as he suggests obtains.

Anthracite may and does occur in sedimentary rocks of varied character,
but, so far as my observation has extended, never in quantity in
sandstone. In the Lower Silurian rocks anthracite occurs, both in the
Old World and in the New, where no metamorphism has affected it, and
where it is simply the normal result of the long continued distillation
of plant tissue; but the anthracite beds which are known and mined in so
many countries are the results of the metamorphism of coal-beds of one
or another age, by local outbursts of trap, or the steaming and baking
of the disturbed strata in mountain chains, numerous instances of which
are given on a preceding page.

M. Mendeleeff, in his article already referred to, misled by a want of
knowledge of the geology of our oil-fields, and ascribing the petroleum
to an inorganic cause, connects the production of oil in Pennsylvania
and Caucasia with the neighboring mountain chains of the Alleghanies and
the Caucasus; but in these localities a sufficient amount of organic
matter can be found to supply a source for the petroleum, while the
upheaval and loosening of the strata along lines parallel with the axes
of elevation has favored the decomposition (spontaneous distillation) of
the carbonaceous strata. It should be distinctly stated, also, that no
igneous rocks are found in the vicinity of productive oil-wells, here or
elsewhere, and there are no facts to sustain the view that petroleum is
a volcanic product.

In the valley of the Mississippi, in Ohio, Illinois, and Kentucky, are
great deposits of petroleum, far removed from any mountain chain or
volcanic vent, and the cases which have been cited of the limited
production of hydrocarbons in the vicinity of, and probably in
connection with, volcanic centers may be explained by supposing that
in these cases the petroleum is distilled from sedimentary strata
containing organic matter by the proximity of melted rock, or steam.

Everything indicates that the distillation which has produced
the greatest quantities of petroleum known was effected at a low
temperature, and the constant escape of petroleum and carbureted
hydrogen from the outcrops of bituminous shales, as well as the result
of weathering on the shales, depriving them of all their carbon, shows
that the distillation and complete elimination of the organic matter
they contain may take place at the ordinary temperature.

* * * * *



For wellnigh two years I have been estimating sulphur in iron and steel
by a modification of the evolution process, which consists in passing
the evolved gases through an ammoniacal solution of peroxide of
hydrogen, which oxidizes the sulphureted hydrogen to sulphuric acid,
which latter is estimated as usual. The _modus operandi_ is as follows:


100 grains of the iron or steel are placed in the 10 oz. flask, a, along
with 1/2 oz. water; 11/2 oz. hydrochloric acid are added from the stoppered
funnel, b, in such quantities at a time as to produce a moderate
evolution of gas through the nitrogen bulb, c, which contains 1/8 oz.
(20 vols.) peroxide of hydrogen and 1/2 oz. ammonia. The tube, d, is to
condense the bulk of the hydrochloric acid which distills over during
the operation. When all the acid has been added and the evolution of gas
becomes sluggish, heat is applied and the liquid boiled till all action
ceases. Air is blown through the aparatus for a few minutes and the
contents of c and d washed into a small beaker and acidified with
hydrochloric acid, boiled, barium chloride added, and the barium
sulphate filtered off after standing a short time. A blank experiment
must be done with each new lot of peroxide of hydrogen obtained, which
always gives under 0.1 barium sulphate with me.

The whole operation is finished within two hours, the usual oxidation
process occupying nearly two days; and the results obtained are
invariably slightly higher than by the oxidation processes.

Until lately I have always added excess of chlorate of potash to the
residue left in a, evaporated it nearly to dryness, diluted, filtered,
and added chloride of barium to the diluted filtrate, but only once
have I obtained a trace of precipitate after standing 48 hours, and the
pig-iron in that case contained 8 per cent. of silicon, so that all
the sulphur is evolved during the process. It has been objected to the
evolution process that when the iron contains copper all the sulphur is
not evolved, but theoretically it ought to be evolved whether copper is
present or not; and to test the point I fused 3 lb. of ordinary Scotch
pig-iron with some copper for half an hour in a Fletcher's gas furnace.
No copper could be detected in the iron by mere observation with a
microscope, but it gave on analysis 0.225 per cent. of copper, and on
estimating the sulphur in it by the above process and by oxidation with
chlorate of potash and hydrochloric acid, using 100 grains in each case,
and performing blank experiments, I found:

By peroxide of hydrogen process 0.0357 per cent.
By oxidation (KClO_{3} and HCl) process, 0.0302 "

so that even in highly cupriferous pig-iron all the sulphur is evolved
on treatment with strong hydrochloric acid.--_Chem. News_.

* * * * *


[Footnote: Abstract of a lecture before the Master Plumbers'
Association, New York, Nov. 2. 1882.]

By Prof. C. F. CHANDLER.

It is only about one hundred years since the first important facts were
discovered which threw light upon the chemistry of atmosphere. It was in
1774 that Dr. Priestley, in London, and Scheele, in Sweden, discovered
the vital constituents of the atmosphere--the oxygen gas which supports
life. The inert gas, nitrogen, had been discovered a year or two before.
When we examine our atmosphere, we find it is composed of oxygen and
nitrogen. The nitrogen constitutes no less than 80 per cent, of the
atmosphere; the remaining 20 percent, consists of oxygen, so that the
atmosphere consists almost entirely of these two gases, odorless and
colorless and invisible. The atmosphere is, however, never free from
moisture; a certain amount of aqueous vapor is always present. The
quantity can hardly be stated, as it varies from day to day and month
to month; it depends upon the temperature and other conditions. Then
we have the gas commonly called carbonic acid in extremely minute
quantities, about one part in 2,500, or four one-hundredths of one per
cent. A small quantity of ammonia and a small quantity of ozone are also

Besides these gases which have been enumerated, and which play an
important part in supporting life in both the kingdoms of nature, we
find a great many solids. Every housewife knows how dust settles upon
everything about the house. This dust has recently been the subject of
most active study, and it proves to be quite as important as the vital
oxygen that actually supports life. When we examine this dust--and it
falls everywhere, not only in the city streets, but upon the tops of
mountains, upon the deck of the ocean steamer, and the Arctic snow--we
find some of it does not belong to the earth, and, as it is not
terrestrial, we call it cosmical. And when it falls in large pieces we
call it a meteorite or shooting star. When the Challenger crossed the
Atlantic, and soundings were made in the deep sea, in the mud that was
brought up and examined there were found various little particles that
were not terrestrial. They were dust particles that were dropped into
the atmosphere of the earth from outer space. Then we have terrestrial
dust, and we divide that into mineral and organic. The mineral consists
chiefly of clay, sand, and, near the ocean, salt. Then we have organic
matter. Some of this is dead leaves which have been ground to powder.
Animal matter has also become dry and reduced to powder, and we actually
find the remains of animals and plants floating upon the atmosphere,
especially in the city. Examinations of the dust which had collected
upon the basement and higher windows of a Fifth avenue residence showed
that the dust upon the basement floor was chiefly composed of sand.
And the higher up I went, the smaller proportion of sand and a larger
proportion of animal matter, so that the dust that blows into our faces
is largely decomposing animal substance.

But we have a living matter in the atmosphere. We often notice in the
summer, after a rain, that the ground is yellow. On gathering up the
yellow powder and examining it under the microscope, we find that it
consists of pollen. The pollen of rag weed and other plants is supposed
to be the cause of hay fever. But we also have something far more
important in the germs of certain classes of vegetation. The effects
are familiar. If food is put away, it becomes mouldy. This mould is a
peculiar kind of vegetation which is called a fungus, and the plants
fungi. In order for this mould to develop a certain temperature and a
certain degree of moisture are necessary. Our food, we say, decays.
Now, what we call decay is really the growth of these fungi. Animal and
vegetable substances which these fungi seize upon are destroyed. All
ordinary fermentations and putrefactions are due to mould fungi, yeast
plants, or bacteria, and liquids undergoing these processes carry these
fungi and their germs wherever they go. The refuse of the city pollutes
the air. You have only to pass along any street to find more or less
rubbish. That furnishes the nidus for the growth and development of
these germs, and until we adopt better methods of getting rid of that
refuse, we never shall have the air of this city in the condition that
it should be.

One of the most constant sources of the pollution of the air in
inhabited localities is the decomposition that takes place in the
ground. Refuse of every kind gets into it. Our sewers are leaky, and
putrefaction is constantly going on. The soil down to the limit of
the ground water contains a large amount of air. This air, when the
atmospheric pressure in the house is diminished, is drawn in with such
organic impurities as it contains. A cement floor in the cellar is not
a protection against this entrance of the ground air, for the cement is
porous to the passage of air, but a remedy may be found by laying on the
cement a covering of coal tar pitch, in which bricks are set on edge,
the spaces between the bricks are filled with the melted pitch, and the
bricks then covered with coal tar pitch. When the house is building, the
foundation walls should also be similarly coated, outside as well as
inside. Such a cellar floor was considered to be absolutely impervious
to ground air and moisture. The lecturer had recently laid this floor in
his own house with the greatest success. The atmosphere of the entire
house is improved, and the expense is very moderate. Another source of
the contamination of the air of houses is the heating apparatus.
Stoves and furnaces, however well constructed at first, will, from the
contraction and expansion of the metal, soon allow the escape of coal
gas, and this danger is greatly increased by the use of dampers in
the stove-pipe. When, to regulate the fire, the damper in the pipe is
closed, the gases, having their passage to the chimney cut off, will
escape through any cracks or openings in the stove into the room.
Prof. Chandler, having kept a record of accidents from this cause, had
accumulated a formidable list of suffocations due to the use of the
damper. The danger was now somewhat lessened by providing dampers with
perforations in the center, which allowed the gases to escape when the
damper was closed. As regards the maintenance of pure air in houses,
the preference was given to the open fire-place. The hot-air furnace
deriving a supply of pure air from out of doors was, when properly
constructed, a very satisfactory method of heating, but in city houses
the mistake was often made of carrying the cold air duct of the furnace
to the front of the house, where it was exposed to the dust of the
streets. It should be taken from the rear end of the house, and carried
some distance above the surface of the yard. It was an excellent
expedient to insert in the cold air duct a wire screen to hold a layer
of cotton to retain the floating impurities which might enter the
air-box. This could be removed from time to time, and the cotton
replaced. Steam heating has been objected to by many for reasons in
no wise due to the apparatus, but to neglect in the use of it. The
complaint of closeness where steam is used is due to the fact that a
room containing a steam radiator can be heated with every door and
window closed, and no fresh air admitted, while with stoves and open
fire-places a certain quantity of fresh air must be admitted to maintain
the fire. Where radiators are used, the ventilation of the rooms should,
therefore, be looked after. Again, the complaint that steam apparatus
has an unpleasant odor is due to the fact that the radiators are allowed
to become covered with dust, which is cooked, and gives rise to the
smells complained of. The radiator should be from time to time
cleaned. When these precautions are taken, no means of heating is more
satisfactory than steam.

Sewer gas is another source of contamination; this is a very indefinite
term, to which formerly many false and exaggerated properties of causing
specific diseases were attributed. It is now, however, recognized to
mean simply the air of sewers, generally not differing very greatly from
common air, containing a certain proportion of marsh gas, carbonic
acid, and sulphureted hydrogen, etc. No one of these gases, however,
is capable of producing the diseases attributed to sewer gas. Careful
research has shown that it is the sewage itself, containing germs of
specific disease, which is added to the air in the sewer by the breaking
of bubbles of gas on its surface, which is the cause of the diseases
associated with sewers.

An intimate connection is believed to exist between the germs of sewer
air and diphtheria, and probably also between sewer air and scarlet
fever. This sewer gas is to be excluded from our houses by proper
systems of plumbing, and to such an extent have these now been
perfected, that there is no objection to having plumbing fixtures in
all parts of the house. This opinion has lately been objected to in the
_Popular Science Monthly_, as it was at a meeting of the Academy of
Medicine last spring, but on wholly insufficient grounds.

The objectors all insist that a trap will allow sewer gas to pass
through it, and the experiments made at the Academy of Medicine showed
that sulphureted hydrogen gas, etc., would so pass. The advocates of the
trap have never denied that the water seal would absorb gases on one
side and give them off on the other, but they do deny that, in the
conditions existing in good plumbing, such gases will be given off in
quantities to do any damage, and they confidently assert that the germ
which is the dangerous element will not pass the seal at all. Pumpelly
investigated the matter for the National Board of Health, and in no
instance was he able to make the germ pass the seal of the trap. It is
now proposed to set up against the weight of this scientific testimony
the results of an investigator in Chicago, whose work was at once
appropriated as an advertisement by stock jobbing disinfectant companies
in a manner which raises a suspicion that the investigation was made in
their interest. He described tersely the essentials of good plumbing,
the necessity of a trap on the house drain, the ventilation of the
soil-pipe, and the ventilation of the trap against siphonage. Of the
first, he said that it offered protection to each householder against
the entrance into his house of the germs of a contagious disease which
passed into the common sewer from the house of a neighbor. Were the trap
dispensed with, the contagion in the sewer would have free entrance into
the houses connecting with it.

Prof. Chandler, in conclusion, alluded to the cordial relations now
existing between the Board of Health and the majority of the master
plumbers of the city. He said that for himself his opinion of the craft
had greatly risen during his intimate connection with plumbers the last
two years. He thought the majority of the jobs now done in the city are
well executed. He believed that the Board of Health had not been obliged
to proceed against more than eight master plumbers since the new law
went into force. He called upon the Association to adopt a "code of
ethics," which should define what an honest plumber can do and cannot
do, and he illustrated his meaning by citing an extraordinary case of
fraudulent workmanship which had been recently reported to him. His
remarks on this point were greeted with frequent outbursts of applause.

* * * * *


The following abstract of a paper read by Dr. Quinlan at the recent
British Pharmaceutical Congress, may prove of interest to medical
readers in this country, where the plant mentioned is a common weed:

"About a year ago Dr. Quinlan had seen the chewed leaves of the
_Plantago lanceolata_ successfully used to stop a dangerous hemorrhage
from leech bites in a situation where pressure could not be employed. He
had searched out the literature of the subject, and found that, although
this herb is highly spoken of by Culpepper and other old writers as
a styptic, and alluded to as such in the plays of Shakespeare, its
employment seems to have died out. Professor Quinlan described the
suitable varieties of plantain, and exhibited preparations which had
been made for him by Dr. J. Evans, of Dublin, State apothecary. They
dried leaves and powdered leaves, conserved with glycerine, for external
use; the juice preserved by alcohol, as also by glycerine, for internal
use; and a green extract. He gave an account of the chemistry of the
juice, from which it appeared that it was not a member of the tannin
series; and also described its physiological effect in causing a
tendency to stasia in the capillaries of the tail of a goldfish,
examined with a microscopic power of 400 X. He regarded its styptic
power as partly mechanical and partly physiological. The juice, in large
doses, he had found useful in internal hemorrhages. The knowledge of
the properties of this plant he thought would be useful in cases of
emergency, because it could be obtained in any field and by the most
uninstructed persons."

* * * * *


Bacteria, whether significant of disease or decline of health, are found
more or less numerous in everything we eat and drink. The germs or
spores of many kinds, known as _termo_, _lineola_, tenue, spirillum,
vibriones, etc, exist in almost infinite numbers; some of the smallest
are too small to be seen by the highest powers, which, being lodged in
all vegetable and animal substances, spring into life and develop very
rapidly under favorable circumstances. They develop most rapidly when
decomposition commences, and seem to indicate the degree or activity
of that decomposition, also hastening the same. They are found most
numerous in the feces, and usually fully developed in the fresh
evacuations of persons of all ages. They may be seen plainly under
a thin glass with high powers with strong or clear light, when the
material is much diluted with water.

These bacteria appear almost as numerously, yet more slowly, in urine,
either upon exposure to air or when freshly evacuated, when the general
health of the individual is declining, or any tendency to decomposition.
A diagnosis can be aided very greatly by a study of these bacteria,
as they indicate or determine the vitality, vigor, and purity of the
system, whether more or less subject to disease, even before any signs
of disease appear. They seem to preindicate the hold of the life force
on the material, and always appear when that force is broken. Their
relative quantity found in feces is as a barometric indication of the
general health or some particular disturbance, and it is surprising
how very fast they multiply while simply passing the intestines under
circumstances favorable for their growth. These forms, so small, are
important, because so very numerous, and their study has been, perhaps,
avoided by many; yet they certainly mean something and effect something,
even the non-malignant varieties as mentioned above, and it is certainly
worth while to continue to study their meaning, even beyond what has
already been written by others on the subject.--_J.M. Adams, in The

* * * * *


(_Soja hispida_.)

A good deal of attention has lately been directed to this plant in
consequence of the enormous extent to which it is cultivated in China
for the sake of the small seeds which it produces, and which are known
as soy beans. These vary considerably in size, shape, and color,
according to the variety of the plant which produces them. They are for
the most part about the size and shape of an ordinary field pea, and,
like the pea, are of a yellow color; some, however, are of a greenish
tint. These seeds contain a large quantity of oil, which is expressed
from them in China and used for a variety of purposes. The residue is
moulded with a considerable amount of pressure into large circular
cakes, two feet or more across, and six inches or eight inches thick.
This cake is used either for feeding cattle or for manuring the land;
indeed, a very large trade is done in China with bean cake (as it is
always called) for these purposes. The well-known sauce called soy is
also prepared from seeds of this bean. The plant generally known as Soja
hispida is by modern botanists referred to Glycine soja. It is an
erect, hairy, herbaceous plant. The leaves are three-parted and the
papilionaceous flowers are born in axillary racemes. It is too tender
for outdoor cultivation in this country, but, has been recommended for
extended growth in our colonies as a commercial plant. The plants are
readily used from seed.--_J.R.F., in The Garden_.

[Illustration: THE SOY BEAN. _(Soja Lispida)_]

* * * * *


The plant of which the illustration is given is one of those fine
specimens which has made the collection of J. Lawless, Esq., The
Cottage, Exeter, famous all over the south and west of England. It is
only one specimen among a considerable collection of hard-wooded plants
which are cultivated and trained in first rate style by Mr. George Cole,
the gardener, one of the most successful plant growers of the day. The
plant was in the winning collection of Mr. Cole exhibited at the late
spring show held at Plymouth.--_The Gardeners' Chronicle_.


* * * * *


We figure this plant, not as a novelty, but for the purpose of showing
what a fine thing it is when grown under propitious circumstances.
Generally, we see it more or less starved in the greenhouse, and even
when planted out in the winter garden its flowers lack the size and
richness of color they attain out-of-doors. It comes from the extreme
south of South America, which accounts for its hardihood, and is a near
ally of the Lapageria: the latter is remarkable for withstanding even
the noxious fumes of the copper smelting works in Chili, and as the
Philesia has similar tough leaves, it is probable that it would support
the vitiated atmosphere of a town better than most evergreens. In any
case, there is no reasonable doubt but that, if cultivators would take
the necessary pains, they might select perfectly hardy varieties both
of the Lapageria and of the Philesia. As it is, we can only call the
Philesea half-hardy north of the Thames, while the Lapageria is not even
that. The curious Philageria, raised in Messrs. Veitch's nursery and
described and figured in our columns in 1872, p. 358, is a hybrid raised
between the two genera. For the specimen of Philesia figured we are
indebted to Mr. Dartnall.--_The Gardeners' Chronicle_.


* * * * *


The mahogany tree, says the _Lumber World_, is a native of the West
Indies, the Bahamas, and that portion of Central America that lies
adjacent to the Bay of Honduras, and has also been found in Florida. It
is stated to be of moderately rapid growth, reaching its full maturity
in about two hundred years. Full grown, it is one of the monarchs of
tropical America. Its trunk, which often exceeds forty feet in length
and six in diameter, and massive arms, rising to a lofty height,
and spreading with graceful sweep over immense spaces, covered with
beautiful foliage, bright, glossy, light, and airy, clinging so long to
the spray as to make it almost an evergreen, present a rare combination
of loveliness and grandeur. The leaves are small, delicate, and polished
like those of the laurel. The flowers are small and white, or greenish
yellow. The fruit is a hard, woody capsule, oval, not unlike the head of
a turkey in size and shape, and contains five cells, in each of which
are inclosed about fifteen seeds.

The mahogany tree was not discovered till the end of the sixteenth
century, and was not brought into European use till nearly a century
later. The first mention of it is that it was used in the repair of
some of Sir Walter Raleigh's ships, at Trinidad, in 1597. Its finely
variegated tints were admired, but in that age the dream of El Dorado
caused matters of more value to be neglected. The first that was brought
to England was about 1724, a few planks having been sent to Dr. Gibbons,
of London, by a brother who was a West Indian captain. The doctor was
erecting a house, and gave the planks to the workmen, who rejected them
as being too hard. The doctor then had a candle-box made of the wood,
his cabinet-maker also complaining of the hardness of the timber.
But, when finished, the box became an object of general curiosity and
admiration. He had one bureau, and her Grace of Buckingham had another,
made of this beautiful wood, and the despised mahogany now became a
prominent article of luxury, and at the same time raised the fortunes
of the cabinet-maker by whom it had been so little regarded. Since that
lime it has taken a leading rank among the ornamental woods, having come
to be considered indispensable where luxury is intended to be indicated.

A few facts will furnish a tolerably distinct idea of the size of this
splendid tree. The mahogany lumbermen, having selected a tree, surround
it with a platform about twelve feet above the ground, and cut it above
the platform. Some twelve or fifteen feet of the largest part of the
trunk are thus lost. Yet a single log not unfrequently weighs from six
or seven to fifteen tons, and sometimes measures as much as seventeen
feet in length and four and a half to five and a half feet in diameter,
one tree furnishing two, three, or four such logs. Some trees have
yielded 12,000 superficial feet, and at average price pieces have sold
for $15,000. Messrs. Broadwood London, pianoforte manufacturers, paid
L3,000 for three logs, all cut from one tree, and each about fifteen
feet long and more than three feet square. The tree is cut at two
seasons of the year--in the autumn and about Christmas time. The trunk,
of course, furnishes timber of the largest dimensions, but that from the
branches is preferred for ornamental purposes, owing to its closer grain
and more variegated color.

In low and damp soil its growth is rapid; but the most valuable trees
grow slowly among rocks on sterile soil, and seem to gather compactness
and beauty from the very struggle which they make for an existence.
In the Bahamas, in the most desolate regions, once flourished that
curiously veined and much esteemed variety once known in Europe as
"Madeira wood," but which has long since been exterminated. Jamaica,
also, which used to be a fruitful source of mahogany, and whence in 1753
not less than 521,000 feet were shipped, is now almost depleted. That
which is now furnished from there is very inferior, pale, and porous,
and is less esteemed than that of Cuba, San Domingo, or Honduras.

In a dry state mahogany Is very durable, and not liable to the attack of
worms, but, when exposed to the weather it does not last long. It would
therefore make excellent material for floors, roofs, etc., but its
costliness limits its utility in this direction, and it is chiefly
employed for furniture, doors, and a few other articles of joinery, for
which it is among the best materials known. It has been used for sashes
and window frames, but is not desirable for this purpose on account of
the ease with which it is affected by the weather. It has also been used
in England to some extent for the framing of machinery in cotton-mills.
Its color is a reddish brown of different shades and luster, sometimes
becoming a yellowish brown, and often much veined and mottled with
darker shades of the same color. Its texture is uniform, and the rings
indicating its annual growth are not very distinct. The larger medullary
rays are absent, but the smaller ones are often very distinct, with
pores between them. In the Jamaica woods these pores are often filled
with a white substance, but in that brought from Central America they
are generally empty. It has neither taste nor odor, shrinks very
slightly, and warps, it is said, less than any other wood.

The variety called Spanish mahogany comes from the West Indies, and is
in smaller logs than the Honduras mahogany, being generally about two
feet square and ten feet long. It is close grained and hard, generally
darker than the Honduras, free from black specks, and sometimes strongly
marked; the pores appear as though chalk had been rubbed into them.

The Honduras mahogany comes in logs from two to four feet square and
twelve to fourteen long; planks have been obtained seven feet wide. Its
grain is very open and often irregular, with black or gray specks. The
veins and figures are often very distinct and handsome, and that of a
fine golden color and free from gray specks is considered the best. It
holds the glue better than any other wood. The weight of a cubic foot of
mahogany varies from thirty-five to fifty-three pounds. Its strength
is between sixty-seven and ninety-six, stiffness seventy-three to
ninety-three, and toughness sixty-one to ninety-nine--oak being
considered as one hundred in each case.

There are three other species of the genus _Swietania_ besides the
mahogany tree, two of them natives of the East Indies. One is a very
large tree, growing in the mountainous parts of central Hindostan, and
rises to a great height, throwing out many branches toward the top. The
head is spreading and the leaves bear some resemblance to those of the
American species. The wood is a dull red, not so beautiful as that known
to commerce, but harder, heavier, and more durable. The natives of India
consider it the most durable timber which their forests afford, and
consequently use it, when it can be procured, wherever strength and
durability are particularly desired. The other East Indian species is
found in the mountains of Sircars, which run parallel to the Bay of
Bengal. The tree is not so large as any of the other species described,
and the wood is of much different appearance, being of a deep yellow,
considerably resembling box. The grain is close, and the wood both heavy
and durable. The third species, known as African mahogany, is brought
from Sierra Leone. It is hard and durable, and used for purposes
requiring these properties in an eminent degree. If, however, the heart
of the tree be exposed or crossed in cutting or trimming the timber, it
is very liable to premature and rapid decay.

* * * * *


In many of the museums efforts are made to perfect economic collections
of animals, so as to show how they can be applied to advantage in the
arts and sciences. The collection and preparation of the corals, for
example, form an important industry. The fossil corals are richly
polished and set in studs and sleeve-buttons, forming rich and
ornamental objects. The fossil coral that resembles a delicate chain has
been often copied by designers, while the red and black corals have long
been used. The best fisheries are along the coasts of Tunis, Algeria,
and Morocco, from 2 to 10 miles from shore, in from 30 to 150 fathoms.
Good coral is also common at Naples, near Leghorn and Genoa, and on
various parts of the sea, as Sardinia, Corsica, Catalonia, Provence,
etc. It ranges in color from pure white through all the shades of
pink, red, and crimson. The rose pink is most valued. For a long time
Marseilles was the market, but now Italy is the great center of the
trade, the greater number of boats hailing from Torre del Greco,
while outside persons are forced to pay a heavy tax. The vessels are
schooners, lateen-rigged, from three to fourteen tons. Large nets are
used, which, during the months between March and October, are dragged,
dredge-like, over the rocks. A large crew will haul in a season from 600
to 900 pounds. To prevent the destruction of the industry, the reef is
divided into ten parts, only one being worked a year, and by the time
the tenth is reached the first is overgrown again with a new growth. In
1873 the Algerian fisheries alone, employing 3,150 men, realized half a
million of dollars. The choice grades are always valuable, the finest
tints bringing over $5 per ounce, while the small pieces, used for
necklaces, and called collette, are worth only $1.50 per ounce. The
large oval pieces are sent to China, where they are used as buttons of
office by the mandarins.


Somewhat similar in appearance to coral is the conch jewelry, sets of
which have been sold for $300. The tint is exquisite, but liable to fade
when exposed to the sun. It is made from the great conch, common in
Southern Florida and the West Indies. The shells are imported into
Europe by thousands, and cut up into studs, sleeve-buttons, and various
articles of ornament. These conches are supposed to be the producers of
pink pearls, but I have opened hundreds of them and failed to find a
single pearl. The conch shell is used by the cameo cutter. Rome and
Paris are the principal seats of the trade, and immense numbers of
shell cameos are imported by England and America, and mounted in rings,
brooches, etc. The one showing a pale salmon-color upon an orange ground
is much used. In 1847, 300 persons worked upon these shells in Paris
alone, the number of shells used being immense. In Paris 300,000
helmet-shells were used in one year, valued at $40,000 of the bull's
mouth, 80,000, averaging a little over a shilling apiece, equal to
$34,000. Eight thousand black helmets were used, valued at $9,000. The
value of the large cameos produced in Paris in the year 1847 was about
$160,000, and the small ones $40,000. In the Wolfe collection of shells
at the Museum of Natural History, Central Park, is a fine specimen of

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