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Scientific American Supplement, No. 363, December 16, 1882 by Various

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SOLDERING WITHOUT AN IRON.

The following method for soldering without the use of a soldering iron
is given in the _Techniker_:

The parts to be joined are made to fit accurately, either by filing
or on a lathe. The surfaces are moistened with the soldering fluid, a
smooth piece of tin foil laid on, and the pieces pressed together and
tightly wired. The article is then heated over the fire or by means of
a lamp until the tin foil melts. In this way two pieces of brass can be
soldered together so nicely that the joint can scarcely be found.

With good soft solder, nearly all kinds of soldering can be done over
a lamp without the use of a "copper." If several piaces have to
be soldered on the same piece, it is well to use solder of unlike
fusibility. If the first piece is soldered with fine solder composed of
2 parts of lead, 1 of tin, and 2 of bismuth, there is no danger of its
melting when another place near it is soldered with bismuth solder, made
of 4 parts of lead, 4 of tin, and 1 of bismuth, for their melting points
differ so much that the former will not melt when the latter does. Many
solders do not form any malleable compounds.

In soldering together brass, copper, or iron, hard solder must be
employed; for example, a solder made of equal parts of brass and silver
(!). For iron, copper, or brass of high melting point, a good solder is
obtained by rolling a silver coin out thin, for it furnishes a tenacious
compound, and one that is not too expensive, since silver stretches out
well. Borax is the best flux for hard soldering. It dissolves the oxides
which form on the surface of the metal, and protects it from further
oxidation, so that the solder comes into actual contact with the
surfaces of the metal. For soft soldering, the well-known fluid, made by
saturating equal parts of water and hydrochloric acid with zinc, is to
be used. In using common solder rosin is the cheapest and best flux. It
also has this advantage, that it does not rust the article that it is
used on.--_Deutsche Industrie Zeitung_.

* * * * *

WORKING COPPER ORES AT SPENCEVILLE.

From a letter in the Grass Valley _Tidings_ we make the following
extracts:

The Spenceville Copper Mining Company have 43 acres of copper-bearing
ground and 100 acres of adjoining land, which was bought for the timber.
There are a hoisting works, mill, roasting sheds, and leaching vats on
the ground, and they cover several acres.

On going around with Mr. Ellis, the first place we came to was the mine
proper, which is simply an immense opening in the ground covering about
one half of an acre, and about 80 feet deep. It has an incline running
down into it, by which the ore is hoisted to the surface. Standing on
the brink of this opening and looking down, we could see the men at
work, some drilling, others filling and running the cars to the incline
to be hoisted to the surface.

The ore is found in a sort of chloritic slate and iron pyrites which
follow the ledge all around. The ore itself is a fine-grained pyrite,
with a grayish color, and it is well suited by its sulphur and low
copper contents, as well as by its properties for heap roasting. In heap
roasting, the ore is hand-broken by Chinamen into small lumps before
being hoisted to the surface. From the landing on the surface it is run
out on long tracks under sheds, dumped around a loose brick flue and on
a few sticks of wood formed in the shape of a V, which runs to the flues
to give a draught. Layers of brush are put on at intervals through the
pile. The smaller lumps are placed in the core of the heap, the larger
lumps thrown upon them, and 40 tons of tank residues thrown over all to
exclude excess of air; 500 lb. of salt is then distributed through the
pile, and it is then set afire. After well alight the draught-holes are
closed up, and the pile is left to burn, which it does for six months.
At the expiration of that time the pile is broken into and sorted, the
imperfectly roasted ore is returned to a fresh roast-heap, and the rest
trammed to the

LEACH-VATS.

These are 50 in number, 10 having been recently added. The first 40 are
four feet by six feet and four feet deep, the remaining 10 twice as
large. About two tons of burnt ore is put in the small vats (twice as
much in the larger ones), half the vats being tilled at one time, and
then enough cold water is turned in to cover the ore. Steam is then
injected beneath the ore, thus boiling the water. After boiling for some
time, the steam is turned off and the water allowed to go cold. The
water, which after the boiling process turns to a dark red color, is
then drawn off. This water carries the copper in a state of solution.
The ore is then boiled a second time, after which the tank residues are
thrown out and water kept sprinkling over them. This water collects the
copper still left in the residues, and is then run into a reservoir, and
from the reservoirs still further on into settling tanks, previous to

PRECIPITATION,

and is then conducted through a system of boxes filled with scrap iron,
thus precipitating the copper.

The richer copper liquors which have been drawn from the tanks fire not
allowed to run in with that which comes from the dump heaps. This liquor
is also run into settling tanks, and from them pumped into four large
barrels, mounted horizontally on friction rollers, to which a very slow
motion is given. These barrels are 18 feet long and six feet six inches
deep outside measure. They are built very strongly, and are water-tight.
Ten tons of scrap iron are always kept in each of these barrels, which
are refilled six times daily, complete precipitation being effected in
less than four hours. Each barrel is provided with two safety valves,
inserted in the heads, which open automatically to allow the escape of
gas and steam. The precipitation of the copper in the barrels forms
copper cement. This cement is discharged from the barrels on to screens
which hold any lumps of scrap iron which may be discharged with the
cement. It is then dried by steam, after which it is conveyed into
another tank, left to cool, and then placed in bags ready for shipment,
as copper cement. The building in which the liquor is treated is the
mill part of the property, from which they send out 42 tons monthly of
an average of 85 per cent, of copper cement, this being the average
yield of the mine.

There are 23 white men and 40 Chinamen employed at the mine and the
mill. There are also several wood choppers, etc., on the company's
pay-roll. Eight months' supply of ore is always kept on hand, there
now being 12,000 tons roasting. The mine is now paying regular monthly
dividends, and everything argues well for the continuance of the same.

* * * * *

SIR WILLIAM THOMSON'S PILE.

The Thomson pile, which is employed with success for putting in action
the siphon recorder, and which is utilized in a certain number of cases
in which an energetic and constant current is needed, is made in two
forms. We shall describe first the one used for demonstration. Each
element of this (Fig. 1) consists of a disk of copper placed at the
bottom of a cylindrical glass vessel, and of a piece of zinc in the form
of a grating placed at the upper part, near the surface of the solution.
A glass tube is placed vertically in the solution, its lower extremity
resting on the copper. Into this tube are thrown some crystals of
sulphate of copper, which dissolve in the liquid, and form a solution of
a greater density than that of the zinc alone, and which, consequently,
cannot reach the zinc by diffusion. In order to retard the phenomenon of
diffusion, a glass siphon containing a cotton wick is placed with one of
its extremities midway between the copper and zinc, and the other in
a vessel outside the element, so that the liquid is sucked up slowly
nearly to its center. The liquid is replaced by adding from the top
either water or a weak solution of sulphate of zinc.

[Illustration: FIG. 1.--THE THOMSON PILE.(Type for demonstration.)]

The greater part of the sulphate of copper that rises through the liquid
by diffusion is carried off by the siphon before reaching the zinc, the
latter being thus surrounded with an almost pure solution of sulphate
of copper having a slow motion from top to bottom. This renewal of the
liquid is so much the more necessary in that the saturated solution of
sulphate of copper has a density of 1.166, and the sulphate of zinc
one of 1.445, There would occur, then, a mixture through inversion of
densities if the solution were allowed to reach a too great amount of
saturation, did not the siphon prevent such a phenomenon by sucking up
the liquid into the part where the mixture tends to take place. The
chemical action that produces the current is identical with that of the
Daniell element.

In its application, this pile is considerably modified in form
and arrangement. Each element (Fig 2) consists of a flat wooden
hopper-shaped trough, about fifty centimeters square, lined with sheet
lead to make it impervious. The bottom is covered with a sheet of copper
and above this there is a zinc grate formed of closely set bars that
allow the liquid to circulate. This grate is provided with a rim which
serves to support a second similar element, and the latter a third,
and soon until there are ten of the elements superposed to form series
mounted for tension. The weight of the elements is sufficient to secure
a proper contact between the zinc and copper of the elements placed
beneath them, such contact being established by means of a band of
copper cut out of the sheet itself, and bent over the trough.

[Illustration: FIG. 2.--THE THOMSON PILE. (Siphon Recorder Type.)]

On account of the large dimensions of the elements, and the proximity
of the two metals, a pile is obtained whose internal resistance is very
feeble, it being always less than a tenth of an ohm when the pile is
in a good state, and the electromotive force being that of the Daniell
element--about 1 08 volts.

Sometimes the zinc is covered with a sheet of parchment which more
thoroughly prevents a mixture of the liquids and a deposit of copper on
the zinc. But such a precaution is not indispensable, if care be taken
to keep up the pile by taking out some of the solution of sulphate of
zinc every day, and adding sulphate of copper in crystals. If the pile
is to remain idle for some time, it is better to put it on a short
circuit in order to use up all the sulphate of copper, the disappearance
of which will be ascertained by the loss of blue color in the liquid. In
current service, on the contrary, a disappearance of the blue color will
indicate an insufficiency of the sulphate, and will be followed by a
considerable reduction in the effects produced by the pile.

The great power of this pile, and its constancy, when it is properly
kept up, constitute features that are indispensable for the proper
working of the siphon recorder--the application for which it was more
especially designed.

This apparatus has been also employed under some circumstances for
producing an electric light and charging accumulators; but such
applications are without economic interest, seeing the enormous
consumption of sulphate of copper during the operation of the pile.
The use of the apparatus is only truly effective in cases where it is
necessary to have, before everything else, an energetic and exceedingly
constant current.--_La Nature_.

* * * * *

SIEMENS' TELEMETER

The accompanying cut illustrates a telemeter which was exhibited at the
Paris Exhibition of Electricity, and which is particularly interesting
from the fact that it is the first apparatus of this kind. It will be
remembered that the object of a telemeter is to make known at any moment
whatever the distance of a movable object, and that, too, by a direct
reading and without any calculation. In Mr. Siemens' apparatus the
problem is solved in the following manner:

The movable object (very often a vessel) is sighted from two different
stations--two points of the coast, for example--by two different
observers. The sighting is done with two telescopes, A1 and A2, which
the observers revolve around a vertical axis by means of two winches, K1
and K2, that gear with two trains of clockwork. There is thus constantly
formed a large triangle, having for its apices the movable point sighted
and the vertical axes, A1 and A2, of the two telescopes. On another
hand, at a point situated between the two telescopes, there is a table,
T T, that carries two alidades, a1v1, and a2v2, movable around their
vertical axes, a1 and a2. The line, a1 a2, that joins these axes is
parallel with that which joins the axes of the two telescopes; and the
alidades are connected electrically with the telescopes by a system
such that each alidade always moves parallel with the telescope that
corresponds to it. It follows from this that the small triangle that
has for apices, a1 a2, and the crossing point of the two alidades will
always be like the large triangle formed by the line that joins the
telescopes and the two lines of vision. If, then, we know the ratio of
a1, a2 to A1 A2, it will suffice to measure on one of the alidades the
distance from its axis to the point of crossing in order to know the
distance from the movable object to the axis of the corresponding
telescope. If the table, T T, be covered with a chart giving the space
over which the ship is moving, so that a1 and a2 shall coincide with the
points which A1 and A2 represent, the crossing of the threads of the
alidades will permit of following on the chart all the ship's movements.
In this way there maybe had a powerful auxiliary in coast defence; for
all the points at which torpedoes have been sunk may be marked on the
chart, and, as soon as the operator at the table finds, by the motion
of the alidades, that the ship under observation is directly over a
torpedo, he will be able to fire the latter and blow the enemy up.
During this time the two observers at A1 and A2 have only to keep their
telescopes directed upon the vessel that it has been agreed upon to
watch.

[Illustration: SIEMENS' ELECTRIC TELEMETER]

In order to obtain a parallelism between the motion of the alidades and
that of the corresponding telescopes, the winch of each of the latter,
while putting its instrument in motion, also sets in motion a Siemens
double-T armature electromagnetic machine. One of the wires of the
armature of this machine, connected to the frame, is always in
communication with the ground at E1 (if we consider, for example, the
telescope to the left), and the other ends in a spring that alternately
touches two contacts. One of these contacts communicates with the
wire, L1 and the other with the wire, L3, so that, when the machine is
revolving, the currents are sent alternately into L1 and L3. These two
latter wires end in a system of electro magnets, M1, provided with a
polarized armature. The motions of the latter act, through an anchor
escapement, upon a system of wheels. An axle, set in motion by the
latter, revolves one way or the other, according to the direction of the
telescope's motions. This axle is provided with an endless screw that
gears with a toothed sector, and the latter controls the rotatory axis
of the alidade. The elements of the toothed wheels and the number of
revolutions of the armature for a given displacement of the telescope
being properly calculated, it will be seen that the alidade will be able
to follow all the movements of the latter.

When it is desired to place one of the telescopes in a given position
(its position of zero, for example), without acting on the alidade,
it may be done by acting directly on the telescope itself without the
intermedium of the winch. For such purpose it is necessary to interrupt
communication with the mechanism by pressing on the button, q. If the
telescope be turned to one side or the other of its normal position,
in making it describe an angle of 90 deg., it will abut against stops, and
these two positions will permit of determining the direction of the
base.

The alidades themselves are provided with a button which disengages the
toothed sector from the endless screw, and permits of their being
turned to a mark made on the table. A regulating screw permits of this
operation being performed very accurately. In what precedes, we have
supposed a case in which the movable point is viewed by two observers,
and in which the table, T T, is stationed at a place distant from them.
In certain cases only two stations are employed. One of the telescopes
is then placed over its alidade and moves with it; and the apparatus
thus comprehends only a system of synchronous movements.

This telemeter was one of the first that was tried in our military
ports, and gave therein most satisfactory results. The maneuver of the
winch, however, requires a certain amount of stress, and in order that
the sending of the currents shall be regular, the operator must turn it
very uniformly. This is a slight difficulty that has led to the use
of piles, instead of the magneto-electric machine, in the apparatus
employed in France. With such substitution there is need of nothing more
than a movable contact that requires no exertion, and that may be guided
by the telescope itself.--_La Lumiere Electrique_.

* * * * *

PHYSICS WITHOUT APPARATUS.

_Experiment in Static Electricity_.--Take a pipe--a common clay one
costing one cent--and balance it carefully on the edge of a goblet, so
that it will oscillate freely at the least touch, like the beam of a
scales. This being done, say to your audience: "Here is a pipe placed
on the edge of a goblet; now the question is to make it fall without
touching it, without blowing against it, without touching the glass,
without agitating the air with a fan, and without moving the supporting
table"

[Illustration: CLAY PIPE ATTRACTED BY AN ELECTRIFIED GOBLET.]

The problem thus proposed may be solved by means of electricity. Take a
goblet like the one that supports the pipe, and rub it briskly against
your coat sleeve, so as to electrify the glass through friction. Having
done this, bring the goblet to within about a centimeter of the pipe
stem. The latter will then be seen to be strongly attracted, and will
follow the glass around and finally fall from its support.

This curious experiment is a pretty variation of the electric pendulum;
and it shows that pipe-clay--a very bad conductor of electricity--favors
very well the attraction of an electrified body.

Tumblers or goblets are to be found in every house, and a clay pipe
is easily procured anywhere. So it would be difficult to produce
manifestations of electricity more easily and at less expense than by
the means here described.--_La Nature_.

* * * * *

THE CASCADE BATTERY.

[Footnote: Lately read before the Society of Telegraph Engineers and
Electricians.]

By F. HIGGINS.

The battery which I have brought here to-night to introduce to your
notice is of the circulating kind, in which the alimentary fluid
employed passes from cell to cell by gravitation, and maintains the
action of the battery as long as it continues to flow. It cannot,
of course, compare with such abundant sources of electricity as
dynamo-electric machines driven by steam power, but for purposes in
which a current of somewhat greater volume and constancy than that
furnished by the ordinary voltaic batteries is required, it will, I
believe, be found in some cases useful. A single fluid is employed, and
each cell is provided with an overflow spout.

The cells are arranged upon steps, in order that the liquid may flow
from the cell on the topmost step through each successive cell by
gravitation [specimen cells were on the table before the audience] to
the reservoir at the bottom. The top and the bottom reservoirs are of
equal capacity, and are fitted with taps. The topmost tap is used to
regulate the flow of the solution, and the bottom one to draw it off. In
each cell two carbon plates are suspended above a quantity of fragments
of amalgamated zinc. The following is a sectional drawing of the
arrangement of the cell:

[Illustration]

A copper wire passes down to the bottom of the cell and makes connection
with the mercury; this wire is covered with gutta-percha, except where
immersed in the mercury. The pores of the carbon plates are filled
with paraffin wax. This battery was first employed for the purpose of
utilizing waste solution from bichromate batteries, a great quantity of
which is thrown away before having been completely exhausted. This waste
is unavoidable, in consequence of the impossibility of permitting such
batteries, when employed for telegraphic purposes, to run until complete
exhaustion or reduction of the solutions has been effected; therefore
some valuable chemicals have to be sacrificed to insure constancy in
working. The fragments of zinc in this cell were also the remains of
amalgamated zinc plates from the bichromate batteries, and the mercury
which is employed for securing good metallic connection is soon
augmented by that remaining after the dissolution of the zinc. It will
therefore be seen that not only the solution, but also the zinc and
mercury remnants of bichromate batteries are utilized, and at the same
time a considerable quantity of electricity is generated. The cells are
seven inches deep and six inches wide, outside, and contain about a
quart of solution in addition to the plates. The battery which I employ
regularly, consisting of 18 cells, is at present working nine permanent
current Morse circuits, which previously required 250 telegraphic
Daniell cells to produce the same effect, and is capable of working at
least ten times the number of circuits which I have mentioned; but as we
do not happen to have any more of such permanent current Morse circuits,
we are unable to make all the use possible of the capabilities of the
battery. The potential of one cell is from 1.9 to 2 volts with strong
solution, and the internal resistance varies from 0.108 to 0.170 of an
ohm with cells of the size described. In order to test the constancy of
the battery, a red heat was maintained in a platinum-iridium wire by the
current for six weeks, both day and night.

The absence or exhaustion of the zinc in any one cell in a battery is
indicated by the appearance of a red insoluble chromic salt of mercury,
in a finely divided state, floating in the faulty cell. It is then
necessary to drop in some pieces of zinc. The state of the zinc supply
may also be ascertained at any time by feeling about in the cells with a
stick. When not required, the battery may be washed by simply charging
the top reservoir with water, and leaving it to circulate in the usual
manner, or the solution may be withdrawn from each cell by a siphon. A
very small flow of the solution is sufficient to maintain the required
current for telegraphic working, but if the flow be stopped altogether
for a few hours, no difference is observed in the current, although when
the current is required to be maintained in a conductor of a few ohms
resistance, as in heating a platinum wire, it is necessary that the
circulation be maintained [heating a piece of platinum ribbon]. The
battery furnishing the current for producing the effect you now see is
of five cells, and as that number is reduced down to two, you see a glow
still appears in the platinum. The platinum strip employed was 5 inches
long and 1/8 inch wide, its resistance being 0.42 ohm, cold. That gives
an idea of the volume of current flowing. I have twelve electro magnets
in printing instruments joined up on the table, and [joining up the
battery] you see that the two cells are sufficient to work them. The
twelve electro-magnets are being worked (by the two cells) in multiple
arc at the same time. The current from the cells which heated the
platinum wire is amply sufficient to magnetize a Thomson recorder. I
have maintained five inches of platinum ribbon in a red hot state for
two hours, in order to make sure that the battery I was about to bring
before you was in good order. The cost of working such a battery when
waste solution cannot be obtained, and it is necessary to use specially
prepared bichromate solution, is about 21/4d. per cell per day, with a
current constantly active in a Thomson recorder circuit, or a resistance
of 11/2 ohms per cell; but if only occasionally used, the same quantity of
solution will last several weeks.

A comparison of this with another form of constant battery, the Daniell,
as used in telegraphy, shows that six of these cells, with a total
electromotive force of 12 volts and an internal resistance of 0.84 of
an ohm, cannot be replaced by less than 71 batteries of 10 cells each,
connected in multiple arc, or for quantity. This result, however large
it may appear, is considerably below that which may be obtained when
working telegraphic lines. A current of 0.02 weber, or ampere, will work
an ordinary sounder or direct writing Morse circuit; the cascade battery
is capable of working 100 such circuits at the same time, while the
combined resistance of that number of lines would not be below that in
which it is found that the battery is constant in action.

Objection may be made to the arrangement of the battery on the score of
waste of zinc by local action, because of the electro positive metal
being exposed to the chromic liquid; but if the battery be out of action
and the circulation stopped, the zinc amalgam is protected by the
immobility of the liquid and the formation of a dense layer of sulphate
of zinc on its surface. When in action, that effect is neutralized from
the fact that carbon in chromic acid is more highly electro-negative
than the chromate of mercury formed upon the zinc amalgam, and which
appears to be the cause of the dissolution of the zinc even when
amalgamated in the presence of chromic acid. The solution may be
repeatedly passed through the battery until the absence of the
characteristic warmth of color of chromic acid indicates its complete
exhaustion. During a description before the Society of thermo-electric
batteries some time ago, Mr. Preece mentioned that five of the
thermopiles which were being tried at the Post-Office were doing the
work of 2,535 of the battery cells previously employed. Thirty of
the cascade cells would have about the same potential as five such
thermopiles, but would supply three and a half times the current, and be
capable of doing the work of 8,872 cells if employed upon the universal
battery system in the same manner as the thermo batteries referred to.

Although this battery will do all that is required for a Thomson
recorder or a similar instrument much more cheaply in this country than
the tray battery, and with half the number of cells, I do not think it
would be the case in distant countries, on account of the difficulty and
cost of transport. A solid compound of chromic and sulphuric acids could
be manufactured which would overcome this difficulty, if permanent
magnetic fields for submarine telegraphic instruments continue to be
produced by electric vortices. In conclusion, and to enable comparisons
to be made, I may mention that the work this battery is capable of
performing is 732,482 foot pounds, at a total cost of 1s. 6d.

* * * * *

[FROM THE SCHOOL JOURNAL.]

PERFECTLY LOVELY PHILOSOPHY.

CHARACTERS: Laura and Isabel, dressed very stylishly, both with hats on.
Enter hand in hand.

_Laura_. My dear Isabel, I was so afraid you would not come. I waited
at that horrid station a full half hour for you. I went there early on
purpose, so as to be sure not to miss you.

_Isabel_. Oh, you sweet girl!

_L_. Now, sit right down; you must be tired. Just lay your hat there on
the table, and we'll begin to visit right off. (_Both lay their hats on
the table and stand near by_.)

_I_. And how have you been all the ages since we were together at
Boston?

_L_. Oh, well, dear; those were sweet old school days, weren't they. How
are you enjoying yourself now? You wrote that you were taking lessons in
philosophy. Tell me how you like it. Is it real sweet?

_I_ Oh, those I took in the winter were perfectly lovely! It was about
science, you know, and all of us just doled on science.

_L_. It must have been nice. What was it about?

_I_. It was about molecules as much as anything else, and molecules are
just too awfully nice for anything. If there's anything I really enjoy,
it's molecules.

_L_. Oh, tell me about them, dear. What are molecules?

_I_. They are little wee things, and it takes ever so many of them, you
know. They are so sweet! Do you know, there isn't anything but that's
got a molecule in it. And the professors are so lovely! They explained
everything so beautifully.

_L_. Oh, how I'd like to have been there!

_I_. You'd have enjoyed it ever so much. They teach protoplasm, too,
and if there's one thing that is too sweetly divine, it's protoplasm. I
really don't know which I like best, protoplasm or molecules.

_L_. Tell me about protoplasm. I know I should adore it!

_I_. 'Deed you would. It's just too sweet to live. You know it's about
how things get started, or something of that kind. You ought to have
heard the professors tell about it. Oh. dear! (_Wipes her eyes with
handkerchief_) The first time he explained about protoplasm there wasn't
a dry eye in the room. We all named our hats after the professors. This
is a Darwinian hat. You see the ribbon is drawn over the crown this way
(_takes hat and illustrates_), and caught with a buckle and bunch of
flowers. Then you turn up the side with a spray of forget me-nots.

_L_. Oh, how utterly sweet! Do tell me some more of science. I adore it
already.

_I_. Do you, dear? Well, I almost forgot about differentiation. I am
really and truly positively in love with differentiation. It's different
from molecules and protoplasms, but it's every bit as nice. And our
professor! You should hear him enthuse about it; he's perfectly bound up
in it. This is a differentiation scarf--they've just come out. All
the girls wear them--just on account of the interest we take in
differentiation.

_L_. What is it, anyway?

_I_. Mull trimmed with Languedoc lace, but--

_L_. I don't mean that--the other.

_I_. Oh, differentiation! That's just sweet. It's got something to
do with species. And we learn all about ascidians, too. They are the
divinest things! If I only had an ascidian of my own! I wouldn't ask
anything else in the world.

_L_. What do they look like, dear? Did you ever see one?

_I_. Oh, no; nobody ever did but the poor dear professors; but they're
something like an oyster with a reticule hung on its belt. I think they
are just _too_ lovely for anything.

_L_. Did you learn anything else besides?

_I_. Oh, yes. We studied common philosophy, and logic, and metaphysics,
and a lot of those ordinary things, but the girls didn't care anything
about those. We were just in ecstasies over differentiations, and
molecules, and the professor, and protoplasms, and ascidians. I don't
see why they put in those common branches; we couldn't hardly endure
them.

_L_. (_Sighs_.) Do you believe they'll have a course like that next
year?

_I_. I think may be they will.

_L_. Dear me! There's the bell to dress for dinner. How I wish I could
study those lovely things!

_I_. You must ask your father if you can't spend the winter in Boston
with me. I'm sure there'll be another course of Parlor Philosophy next
winter. But how dreadful that we must stop talking about it now to dress
for dinner! You are going to have company, you said; what shall you
wear, dear?

_L_. Oh, almost anything. What shall you?

(_Exeunt arm in arm_.)

* * * * *

THE PROPOSED DUTCH INTERNATIONAL COLONIAL AND GENERAL EXPORT EXHIBITION.

The Amsterdam International Exhibition, the opening of which has been
fixed for May 1, 1883, is now in way of realization. This exhibition
will present a special interest to all nations, and particularly to
their export trade. Holland, which is one of the great colonial powers,
proposes by means of this affair to organize a competition between the
various colonizing nations, and to contribute thus to a knowledge of
the resources of foreign countries whose richness of soil is their
fundamental power.

The executive committee includes the names of some of the most prominent
persons of the Netherlands: M. Cordes, president; M. de Clercq,
delegate; M. Kappeyne van di Coppello, secretary; and M. Agostini,
commissary general.

[Illustration: PLAN OF THE DUTCH INTERNATIONAL EXHIBITION.

1. Exhibition Palace.
2. Netherlands Colonial Exhibition.
3. Fine Arts.
4. Annexes for Agricultural Machines, etc.
5. Machines, Materials, etc.
6. Concert Theater.
7. Panorama.
8. Jury Pavilion.
9. Royal Pavilion.
10. Committee Pavilion.
11. International Society's Pavilion.
12. Restaurant and Cafe.
13. Music Kiosque and Electric Pharos.
14. German Restaurant.
15. Dutch Restaurant.
16. English Restaurant.
17. French Restaurant.
18. Aquarium and Rockwork.
]

The exhibition will consist of five great divisions, to wit: 1. A
Colonial exhibition. 2. A General Export exhibition. 3. A Retrospective
exhibition of Fine Arts and of Arts applied to the Industries. 4.
Special exhibitions. 5. Lectures and Scientific Reunions.

The colonial part forms the base of the exhibition, and will be devoted
to a comparative study of the different systems of colonization
and colonial agriculture, as well as of the manners and customs of
ultramarine peoples. In giving an exact idea of what has been done, it
will indicate what remains to be done from the standpoint of a general
development of commerce and manufactures. Such is the programme of the
first division.

The second division will include everything that relates to the export
trade.

The third division will be reserved for works of art dating back from
the most remote ages.

The fourth division will be devoted to temporary exhibitions, such as
those of horticultural and agricultural products, etc.

The fifth division will constitute the intellectual part, so to speak,
of the exhibition. It will be devoted to lectures, and to scientific
meetings for the discussion of questions relating to teaching, to the
arts, to the sciences, to hygiene, to international jurisprudence, and
to political economy. Questions of colonial economy will naturally
occupy the first rank.

As will be seen, the programme of this grand scheme organized by the
Netherlands government is a broad one; and, owing the experience
acquired in recent universal exhibitions, especially that of Paris in
1878, very happy results may be expected from it.

At present, we give an illustration showing the general plan of the
exhibition. In future, in measure as the work proceeds, we shall be able
to give further details.--_Le Genie Civil_.

* * * * *

NEW METHOD OF DETECTING DYES ON YARNS AND TISSUES.

By JULES JOFFRE.

The reagents employed are a solution of caustic potassa in ten parts
of water; hydrochloric acid diluted with an equal bulk of water, or
occasionally concentrated; nitric acid, ammonia, ferric sulphate, and
a concentrated solution of tin crystals. The most convenient method of
operating is to steep small portions of the cloth under examination in a
little of the reagent placed at the bottom of a porcelain capsule. The
bits are then laid on the edge of the capsule, when the changes of color
which they have undergone may be conveniently observed. It is useful to
submit to the same reagents simultaneously portions of cloth dyed in a
known manner with the wares which are suspected of having been used in
dyeing the goods under examination.

RED COLORS.

By the action of caustic potassa, the reds are divided into four groups:
1, those which turn to a violet or blue; 2, those which turn brown;
3, those which are changed to a light yellow or gray; 4, those which
undergo little or no change.

The first group comprises madder, cochineal, orchil, alkanet, and
murexide. Madder reds are turned to an orange by hydrochloric acid,
while the three next are not notably affected. Cochineal is turned by
the potassa to a violet-red, orchil to a violet-blue, and alkanet to a
decided blue. Lac-dye presents the same reactions as cochineal, but
has less brightness. Ammoniacal cochineal and carmine may likewise be
distinguished by the tone of the reds obtained.

A characteristic of madder reds is that, after having been turned yellow
by hydrochloric acid, they are rendered violet on treatment with milk
of lime. A boiling soap-lye restores the original red, though somewhat
paler. Artificial alizarine gives the same reaction. Turkey-reds,
however, are quite unaffected by acid. Garancine and garanceux reds, if
treated first with hydrochloric acid and then with milk of lime, turn to
a dull blue.

Madder dyes are sometimes slow in being turned to a violet by potassa,
and this shade when produced is often brownish. They might thus be
confounded with the dyes of the fourth group, i.e., rosolic acid,
coralline, eosine, and coccine. None of these colors gives the
characteristic reaction with milk of lime and boiling soap-lye. If
plunged in milk of lime, they resume their rose or orange shades, while
the madder colors become violet. Murexide is turned, by potassa, gray
in its light shades and violet in its dark ones. It might, then, be
confounded with orchil, but it is decolorized by hydrochloric acid,
which leaves orchil a red. Moreover, it is turned greenish by stannous
chloride.

A special character of this dye (murexide) is the presence of mercury,
the salts of which serve as mordants for fixing it, and may be detected
by the ordinary reagents.

The second group comprises merely sandal wood or sanders red, which
turns to a brown. On boiling it with copperas it becomes violet, while
on boiling with potassium dichromate it changes to a yellowish brown.

The third group includes safflower, magenta, and murexide (light
shades). If the action of the potassa is prolonged the (soft) red woods
enter into this group. Safflower turns yellow by the action of potassa,
and the original rose shade is not restored by washing with water.
Hydrochloric acid turns it immediately yellow. Citric acid has no
action. Magenta is completely decolorized by potassa, but a prolonged
washing in water reproduces the original shade. This reaction is common
to many aniline colors. These decolorations and recolorations are easily
produced in dark shades, while in very light shades they are less easily
observed, because there is always a certain loss of color. Stannous
chloride turns magenta reds to a violet. Hydrochloric acid renders them
yellowish brown (afterward greenish?). Water restores the purple red
shade.

The fourth group comprises saffranine, azo-dinaphthyldiamine, rosolic
acid, coralline, pure eosine and cosine modified by a salt of lead,
coccina, artificial ponceau, and red-wood.

Saffranine is detected by the action of hydrochloric acid, which turns
it to a beautiful blue; the red color is restored by washing in water.
Azo-dinaphthyl diamine is recognized by its peculiar orange cast, and is
turned by hydrochloric acid to a dull, dirty violet. Rosolic acid and
coralline, as well as eosine, are turned by hydrochloric acid to an
orange-yellow: the two former are distinguished from eosine by their
shade, which inclines to a yellow. Potassa turns rosolic acid and
coralline from an orange-red to a bright red, while it produces no
change in eosine. If the action of potassa is prolonged, modified eosine
is blackened in consequence of the decomposition of the wool, the
sulphur of which forms lead sulphide. Coccine becomes of a light
lemon-yellow on treatment with hydrochloric acid. Washing with water
restores the original shade. It affords the same reactions as eosine,
but its tone is more inclined to an orange.

Artificial ponceau does not undergo any change on treatment with
hydrochloric acid, and resists potash. Red wood shades are turned toward
a gooseberry-red by hydrochloric acid, especially if strong. This last
reaction not being very distinct, red-wood shades might be mistaken
for those of artificial ponceau but for the superior brightness of the
latter. If the action of potassa is prolonged, the red-wood shades
are decolorized, and a washing with water then bleaches the tissue.
Rocelline affords the same reactions as artificial ponceau, but if
steeped in a concentrated solution of stannous chloride it is in time
completely discharged, which is not the case with artificial ponceau.

VIOLET COLORS.

Violets are divided into two groups: those affected by potassa, and
those upon which it has no action. The first group embraces logwood,
orchil, alkanet, and aniline violets, including under the latter term
Perkin's violet, (probably the original "mauve"), dahlia, Parme or
magenta violet, methyl, and Hofmann's violets. The action of potassa
gives indications for each of these violets. Logwood violet is browned;
that of orchil, if slightly reddish, is turned to a blue-violet; that of
alkanet is modified to a fine blue. Lastly, Perkin's mauve, dahlia, and
methyl violet become of a grayish brown, which may be re-converted into
a fine violet by washing in abundance of water. When the shades are
very heavy, this grayish brown is almost of a violet-brown, so that the
violets might seem to be unaltered.

The action of hydrochloric acid distinguishes these colors better still
if the aid of ammonia is called in for two cases.

The acid turns logwood violet to a fine red, and equally reddens orchil
violet. But the two colors cannot be confounded, first, because the two
violet shades are very distinct, that of orchil being much the brighter;
and secondly, because ammonia has no action on logwood violet, while it
turns orchil violet, if at all reddish, to a blue shade. Hydrochloric
acid, whether dilute or concentrated, is without action on alkanet
violet. If the acid is dilute, it is equally without action on Perkin's
violet and dahlia. If it is strong, it turns them blue, and even green
if in excess. Hofmann's violet turns green even with dilute acid, but
prolonged washing restores the original violet shade. Dahlia gives a
more blue shade than Perkin's mauve. The action of acid is equally
characteristic for methyl violet. It becomes green, then yellow. Washing
in water re-converts it first to a green, and then to a violet.

The second group includes madder violet, cochineal violet, and the
compound violet of cochineal and extract of indigo. These three dyes are
thus distinguished: Hydrochloric acid turns the madder violet-orange,
slightly brownish, or a light brown, and it affords the characteristic
reaction of the madder colors described above under reds. Cochineal
violets are reddened. Sometimes they are decolorized, and become finally
yellow, but do not pass through a brown stage.

The compound violet of cochineal and extract of indigo presents this
characteristic reaction, that if boiled with very weak solution of
sodium carbonate the liquid becomes blue, rather greenish, while the
cloth becomes a vinous-red--_Moniteur Scientifique.--Chem. News._

* * * * *

CHEVALET'S CONDENSO-PURIFIER FOR GAS.

The condenso-purifier shown in the accompanying cut operates as
follows: Water is caused to flow over a metallic plate perforated with
innumerable holes of from one to three millimeters in diameter, and
then, under this disk, which is exactly horizontal, a current of gas is
introduced. Under these circumstances the liquid does not traverse the
holes in the plate, but is supported by the gas coming in an opposite
direction. Provided that the gas has sufficient pressure, it bubbles up
through the water and becomes so much the more divided in proportion as
the holes are smaller and more numerous.

The gas is washed by traversing the liquid, and freed from the tar and
coal-dust carried along with it; while, at the same time, the ammonia
that it contains dissolves in the water, and this, too, so much the
better the colder the latter is. This apparatus, then, permits of
obtaining two results: a mechanical one, consisting in the stoppage of
the solid matters, and a chemical one, consisting in the stoppage of the
soluble portions, such as ammonia, sulphureted hydrogen, and carbonic
acid.

[Illustration: FIG. 1.--CONDENSO-PURIFIER FOR GAS. (Elevation.)]

The condenso-purifier consists of three perforated diaphragms, placed
one over the other in rectilinear cast-iron boxes. These diaphragms are
movable, and slide on projections running round the interior of the
boxes. In each of the latter there is an overflow pipe, g, that runs to
the box or compartment below, and an unperforated plate, f, that slides
over the diaphragm so as to cover or uncover as many of the holes as may
be necessary. A stream of common water runs in through the funnel, e,
over the upper diaphragm, while the gas enters the apparatus through the
pipe, a, and afterward takes the direction shown by the arrows.
Reaching the level of the overflow, the water escapes, fills the lower
compartment, covers the middle diaphragm, then passes through the second
overflow-pipe to cover the lower diaphragm, next runs through the
overflow-pipe of the third diaphragm on to the bottom of the purifier,
and lastly makes its exit, through a siphon. A pressure gauge, having an
inlet for the gas above and below, serves for regulating the pressure
absorbed for each diaphragm, and which should vary between 0.01 and
0.012 of a meter.

The effect of this purifier is visible when the operation is performed
with an apparatus made externally of glass. The gas is observed to enter
in the form of smoke under the first diaphragm, and the water to become
discolored and tarry. When the gas traverses the second diaphragm, it is
observed to issue from the water entirely colorless, while the latter
becomes slightly discolored, and finally, when it traverses the third
diaphragm, the water is left perfectly limpid.

Two diaphragms have been found sufficient to completely remove the solid
particles carried along by the gas, the third producing only a chemical
effect.

This apparatus may replace two of the systems employed in gas works: (1)
mechanical condensers, such as the systems of Pelouze & Audouin, and
of Servier; and (2) scrubbers of different kinds and coke columns.
Nevertheless, it is well to retain the last named, if the gas works have
them, but to modify their work.

[Illustration: FIG. 2.--PLAN VIEW WITH BY-PASS.]

This purifier should always be placed directly after the condensers, and
is to be supplied with a stream of pure water at the rate of 50 liters
of water per 1,000 cubic meters of gas. Such water passes only once into
the purifier, and issues therefrom sufficiently rich in ammonia to be
treated.

If there are coke columns in the works, they are placed after the
purifier, filled with wood shavings or well washed gravel, and then
supplied with pure cold water in the proportion stated above. The water
that flows from the columns passes afterward into the condenso-purifier,
where it becomes charged with ammonia, and removes from the gas the tar
that the latter has carried along, and then makes its exit and goes to
the decanting cistern.

In operating thus, all the remaining ammonia that might have escaped the
condenso-purifier is removed, and the result is obtained without pumps
or motor, with apparatus that costs but little and does not occupy much
space. The advantages that are derived from this, as regards sulphate
of ammonia, are important; for, on treating ammoniacal waters with
condensers, scarcely more than four to five kilogrammes of the sulphate
are obtained per ton of coal distilled, while by washing the gas
perfectly with the small quantity of water indicated, four to five
kilogrammes more can be got per 1,000 kilogrammes of coal, or a total of
eight to ten kilogrammes per ton.

When the gas is not washed sufficiently, almost all of the ammonia
condenses in the purifying material.

The pressure absorbed by the condenso purifier is from ten to twelve
millimeters per washing-diaphragm. In works that are not provided with
an extractor, two diaphragms, or even a single one, are employed when it
is desired simply to catch the tar.

The apparatus under consideration was employed in the St. Quentin
gas works during the winter of 1881-1882, without giving rise to any
obstruction; and, besides, it was found that by its use there might be
avoided all choking up of the pipes at the works and the city mains
through naphthaline.

In cases of obstruction, it is very easy to take out the perforated
diaphragms; this being done by removing the bolts from the piece that
holds the register, f, and then removing the diaphragm and putting in
another. This operation takes about ten minutes. The advantages of such
a mounting of the diaphragms is that it allows the gas manufacturer to
employ (and easily change) the number of perforations that he finds best
suited to his needs.

These apparatus are constructed for productions of from 1,000 to 100,000
cubic meters of gas per twenty four hours. They have been applied
advantageously in the washing of smoke from potassa furnaces, in order
to collect the ammonia that escapes from the chimneys. In one of such
applications, the quantity of gas and steam washed reached a million
cubic meters per twenty-four hours.--_Revue Industrielle._

* * * * *

ARTIFICIAL IVORY.

It is said that artificial ivory of a pure white color and very durable
has been manufactured by dissolving shellac in ammonia, mixing the
solution with oxide of zinc, driving off ammonia by heating, powdering,
and strongly compressing in moulds.

* * * * *

CREOSOTE IMPURITIES.

[Footnote: Read at the meeting of the American Pharmaceutical
Association held at Niagara Falls. 1882.]

By Prof. P. W. BEDFORD.

The object of this query can be but one, namely, to inquire whether the
wood creosote offered for sale is a pure article, or not; and if not,
what is the impurity present?

The relative commercial value of the articles sold as coal tar creosote
and wood creosote disposes of the question as to the latter being
present in the former article, and we are quite certain that the cheap
variety is nothing more or less than a phenol or carbolic acid. Wood
creosote, it has been frequently stated, is adulterated with coal tar
creosote, or phenol. The object of my experiments has been to prove the
identity of wood creosote and its freedom from phenol. The following
tests are laid down in various works as conclusive evidence of its
purity, and each has been fully tried with the several samples of wood
creosote to prove their identity and purity, and also with phenol, sold
as commercial creosote or coal tar creosote, and for comparison with
mixtures of the two, that even small percentages of admixture might be
identified, should such exist in the wood creosote of the market.

The following tests were used:

1. Equal volumes of anhydrous glycerine and wood creosote make a turbid
mixture, separating on standing. _Phenol dissolves_. If three volumes
of water be added, the separation of the wood creosote is immediate.
_Phenol remains in permanent solution_.

2. One volume of wood creosote added to two volumes of glycerine; the
former is not dissolved, but separates on standing. _Phenol dissolves_.

3. Three parts of a mixture containing 75 per cent, of glycerine and
25 of water to 1 part of wood creosote show no increase of volume of
glycerine, and wood creosote separates. _Phenol dissolves, and forms
a clear mixture_. Were any phenol present in the wood creosote, the
increase in the volume of the glycerine solution, if in a graduated
tube, would distinctly indicate the percentage of phenol present.

4. Solubility in benzine. Wood creosote entirely soluble. _Phenol is
insoluble_.

5. A 1 per cent, solution of wood creosote. Take of this 10 cubic
centimeters, add 1 drop of a test solution of ferric chloride; an
evanescent blue color is formed, passing quickly into a red color.
_Phenol gives a permanent blue color_.

6. Collodion or albumen with an equal bulk of wood creosote makes a
perfect mixture without coagulation. _Phenol at once coagulates into a
more or less firm mass or clot_.

7. Bromine solution with wood creosote gives a reddish brown
precipitate. _Phenol gives a white precipitate_.

All tests enumerated above were repeatedly tried with four samples of
wood creosote sold as such; one a sample of Morson's, one of Merck's,
one evidently of German origin, but bearing the label and capsule of an
American manufacturer, and one of unknown origin, but sold as beech-wood
creosote (German), and each proved to be _pure wood creosote_.

Two samples of commercial creosote which, from the low cost, were known
to be of coal tar origin gave the negative tests, showing that they were
phenol.

Corroborative experiments were made by mixing 10 to 20 per cent, of
phenol with samples of the beechwood creosote, but in every case each of
the tests named showed the presence of the phenol.

The writer on other occasions applied single tests (the collodion test)
to samples of beechwood creosote that he had an opportunity of procuring
small specimens of, and satisfied himself that they were pure. The
conclusion is that the wood creosote of the market of the present time
is in abundant supply, is of unexceptionable quality, and reasonable in
price, so that there is no excuse for the substitution of the phenol
commonly sold for it. When it is directed for use for internal
administration (the medicinal effect being entirely dissimilar), wood
creosote only should be dispensed.

The general sales of creosote by the pharmacist are in small quantities
as a toothache remedy, and phenol has the power of coagulating albumen,
which effectually relieves the suffering. Wood creosote does not
coagulate albumen, and is, therefore, not as serviceable. This is,
perhaps, the reason that it has become, in a great measure, supplanted
in general sale by the coal tar creosote, to say nothing of the argument
of a lower cost.

* * * * *

REMEDY FOR SICK HEADACHE.

Surgeon Major Roehring, of Amberg, reports, in No. 32 of the _Allg. Med.
Centr. Zeit_., April 22, 1882, a case of headache of long standing,
which he cured by salicylate of sodium, which confirms the observations
of Dr. Oehlschlager, of Dantzig, who first contended that we possessed
in salicylic acid one of the most reliable remedies for neuralgia. This
cannot astonish us if we remember that the action of salicylic acid is,
in more than one respect, and especially in its influence on the nervous
centers, analogous to quinine.

While out with the troops on maneuver, Dr. Roehring was called to visit
the sixteen-year old son of a poor peasant family in a neighboring
village. The boy, who gave all evidences of living under bad hygienic
surroundings, but who had shown himself very diligent at school, had
been suffering, from his sixth year, several days every week from the
most intense headache, which had not been relieved by any of the many
remedies tried for this purpose. A careful examination did not reveal
any organic lesion or any cause for the pain, which seemed to be
neuralgic in character, a purely nervous headache. Roehring had just
been reading the observations of Oehlschlager, and knowing, from the
names of the physicians who had been already attending the poor boy,
that all the common remedies for neuralgia had been given a fair trial,
thought this a good opportunity to test the virtue of salicylate of
sodium. He gave the boy, who, in consequence of the severity of the
pain, was not able to leave his bed, ten grains of the remedy every
three hours, and was surprised to see the patient next day in his tent
and with smiling face. The boy admitted that he for years had not been
feeling so well as he did then. The remedy was continued, but in less
frequent doses, for a few days longer; the headache did not return.
Several months later Dr. Roehring wrote to the school-teacher of the
boy, and was informed that the latter had, during all this time,
been totally free of his former pain, that he was much brighter than
formerly, and evidently enjoying the best of health.

It may be worth while to give the remedy a more extensive trial, and the
more so as we are only too often at a loss what to do in stubborn cases
of so-called nervous headache.--_The Medical and Surgical Reporter_.

* * * * *

SUNLIGHT AND SKYLIGHT AT HIGH ALTITUDES.

At the Southampton meeting of the British Association, Captain Abney
read a paper in which he called attention to the fact that photographs
taken at high altitudes show skies that are nearly black by comparison
with bright objects projected against them, and he went on to show that
the higher above the sea level the observer went, the darker the sky
really is and the fainter the spectrum. In fact, the latter shows but
little more than a band in the violet and ultraviolet at a height of
8,500 feet, while at sea-level it shows nearly the whole photographic
spectrum. The only reason of this must be particles of some reflecting
matter from which sunlight is reflected. The author refers this to
watery stuff, of which nine-tenths is left behind at the altitude at
which be worked. He then showed that the brightness of the ultra-violet
of direct sunlight increased enormously the higher the observer went,
but only to a certain point, for the spectrum suddenly terminated about
2,940 wave-length. This abrupt absorption was due to extra-atmospheric
causes and perhaps to space. The increase in brightness of the
ultra-violet was such that the usually invisible rays, L, M, N, could be
distinctly seen, showing that the visibility of these rays depended
on the intensity of the radiation. The red and ultra-red part of the
spectrum was also considered. He showed that the absorption lines were
present in undiminished force and number at this high altitude, thus
placing their origin to extra-atmospheric causes. The absorption from
atmospheric causes of radiant enemy in these parts he showed was due
to "water-stuff," which he hesitated to call aqueous vapor, since the
banded spectrum of water was present, and not lines. The B and A line he
also stated could not be claimed as telluric lines, much less as due to
aqueous vapor, but must originate between the sun and our atmosphere.
The author finally confirmed the presence of benzine and ethyl in the
same region. He had found their presence indicated in the spectrum at
sea-level, and found their absorption lines with undiminished intensity
at 8,500 feet. Thus, without much doubt, hydrocarbons must exist between
our atmosphere and the sun, and, it may be, in space.

Prof. Langley, following Capt. Abney, observed: The very remarkable
paper just read by Captain Abney has already brought information
upon some points which the one I am about, by the courtesy of the
Association, to present, leaves in doubt. It will be understood then
that the references here are to his published memoirs only, and not to
what we have just heard.

The solar spectrum is so commonly composed to have been mapped with
completeness, that the statement that much more than one-half its extent
is not only unmapped but nearly unknown, may excite surprise. This
statement is, however, I think, quite within the truth, as to that
almost unexplored region discovered by the elder Herschel, which, lying
below the red and invisible to the eye, is so compressed by the prism
that, though its aggregate heat effects have been studied through the
thermopile, it is only by the recent researches of Capt. Abney that we
have any certain knowledge of the lines of absorption there, even in
part. Though the last-named investigator has extended our knowledge of
it to a point much beyond the lowest visible ray, there yet remains a
still remoter region, more extensive than the whole visible spectrum,
the study of which has been entered on at Alleghany, by means of the
linear bolometer.

The whole spectrum, visible and invisible, is powerfully affected by the
selective absorption of our atmosphere and that of the sun; and we must
first observe that could we get outside our earth's atmospheric shell,
we should see a second and very different spectrum, and could we
afterward remove the solar atmosphere also, we should have yet a third,
different from either. The charts exhibited show:

1st. The distribution of the solar energy as we receive it, at the
earth's surface, throughout the entire invisible as well as visible
portion, both on the prismatic and normal scales. This is what I have
principally to speak of now, but this whole first research is but
incidental to others upon the spectra before any absorption, which
though incomplete, I wish to briefly allude to later. The other curves
then indicate:

2d. The distribution of energy before absorption by our own atmosphere.

3d. This distribution at the photosphere of the sun. The extent of
the field, newly studied, is shown by this drawing [chart exhibited].
Between H in the extreme violet, and A in the furthest red, lies the
visible spectrum, with which we are familiar, its length being about
4,000 of Angstrom's units. If, then, 4,000 represent the length of the
visible spectrum, the chart shows that the region below extends through
24,000 more, and so much of this as lies below wave-length 12,000, I
think, is now mapped for the first time.

[Illustration: FIG. 1.--PRISMATIC SPECTRUM.]

We have to pi = 12,000 relatively complete photographs, published by
Capt. Abney, but, except some very slight indications by Lamansky,
Desains, and Mouton, no further guide.

Deviations being proportionate to abscissae, and measured solar energies
to ordinates, we have here (1) the distribution of energy in the
prismatic, and (2) its distribution in the normal spectrum. The total
energy is in each case proportionate to the area of the curve (the two
very dissimilar curves inclosing the same area), and on each, if the
total energy be roughly divided into four parts, one of these will
correspond to the visible, and three to the invisible or ultra-red part.
The total energy at the ultra violet end is so small, then, as to be
here altogether negligible.

We observe that (owing to the distortion introduced by the prism) the
maximum ordinate representing the heat in the prismatic spectrum is, as
observed by Tyndall, below the red, while upon the normal scale this
maximum ordinate is found in the orange.

I would next ask your attention to the fact that in either spectrum,
below pi = 12,000 are most extraordinary depressions and interruptions
of the energy, to which, as will be seen, the visible spectrum offers
no parallel. As to the agent producing these great gaps, which so
strikingly interrupt the continuity of the curve, and, as you see,
in one place, cut it completely into two, I have as yet obtained no
conclusive evidence. Knowing the great absorption of water vapor in this
lowest region, as we already do, from the observations of Tyndall, it
would, _a priori_, seem not unreasonable to look to it as the cause. On
the other hand, when I have continued observations from noon to sunset,
making successive measures of each ordinate, as the sinking sun sent its
rays through greater depths of absorbing atmosphere, I have not found
these gaps increasing as much as they apparently should, if due to a
terrestrial cause, and so far as this evidence goes, they might be
rather thought to be solar. But my own means of investigation are not so
well adapted to decide this important point as those of photography, to
which we may yet be indebted for our final conclusion.

[Illustration: FIG. 2.--NORMAL SPECTRUM. (At sea level.)]

I am led, from a study of Capt. Abney's photographs of the region
between pi = 8,000 and pi = 12,000, to think that these gaps are
produced by the aggregation of finer lines, which can best be
discriminated by the camera, an instrument which, where it can be used
at all, is far more sensitive than the bolometer; while the latter, I
think, has on the other hand some advantage in affording direct and
trustworthy measures of the amount of energy inhering in each ray.

One reason why the extent of this great region has been so singularly
underestimated, is the deceptively small space into which it appears to
be compressed by the distortion of the prism. To discriminate between
these crowded rays, I have been driven to the invention of a special
instrument. The bolometer, which I have here, is an instrument depending
upon principles which I need not explain at length, since all present
may be presumed to be familiar with the success which has before
attended their application in another field in the hands of the
President of this Association.

I may remark, however, that this special construction has involved very
considerable difficulties and long labor. For the instrument here shown,
platinum has been rolled by Messrs. Tiffany, of New York, into sheets,
which, as determined by the kindness of Professor Rood, reach the
surprising tenuity of less than one twenty-five-thousandth of an English
inch (I have also iron rolled to one fifteen-thousandth inch), and from
this platinum a strip is cut one one-hundred-and-twenty-fifth of an inch
wide. This minute strip, forming one arm of a Wheatstone's bridge, and
thus perfectly shielded from air currents, is accurately centered by
means of a compound microscope in this truly turned cylinder, and the
cylinder itself is exactly directed by the arms of this Y.

The attached galvanometer responds readily to changes of temperature, of
much less than one-ten-thousandth degree F. Since it is one and the same
solar energy whose manifestations we call "light" or "heat," according
to the medium which interprets them, what is "light" to the eye is
"heat" to the bolometer, and what is seen as a dark line by the eye is
felt as a cold line by the sentient instrument. Accordingly, if lines
analogous to the dark "Fraunhofer lines" exist in this invisible region,
they will appear (if I may so speak) to the bolometer as cold bands, and
this hair-like strip of platina is moved along in the invisible part of
the spectrum till the galvanometer indicates the all but infinitesimal
change of temperature caused by its contact with such a "cold band." The
whole work, it will be seen, is necessarily very slow; it is in fact a
long groping in the dark, and it demands extreme patience. A portion of
its results are now before you.

The most tedious part of the whole process has been the determination of
the wave-lengths. It will be remembered that we have (except through the
work of Capt. Abney already cited, and perhaps of M. Mouton) no direct
knowledge of the wave-lengths in the infra-red prismatic spectrum, but
have hitherto inferred them from formulas like the well-known one of
Cauchy's, all which known to me appear to be here found erroneous by the
test of direct experiment, at least in the case of the prism actually
employed.

I have been greatly aided in this part of the work by the remarkable
concave gratings lately constructed by Prof. Rowland, of Baltimore, one
of which I have the pleasure of showing you. [Instrument exhibited.]

The spectra formed by this fall upon a screen in which is a fine slit,
only permitting nearly homogeneous rays to pass, and these, which may
contain the rays of as many as four overlapping spectra, are next passed
through a rock-salt or glass prism placed with its refracting edge
parallel to the grating lines. This sorts out the different narrow
spectral images, without danger of overlapping, and after their passage
through the prism we find them again, and fix their position by means of
the bolometer, which for this purpose is attached to a special kind of
spectrometer, where its platinum thread replaces the reticule of the
ordinary telescope. This is very difficult work, especially in the
lowermost spectrum, where I have spent over two weeks of consecutive
labor in fixing a single wave-length.

The final result is, I think, worth, the trouble, however, for, as you
see here, we are now able to fix with approximate precision and by
direct experiment, the wave-length of every prismatic spectral ray. The
terminal ray of the solar spectrum, whose presence has been certainly
felt by the bolometer, has a wave-length of about 28,000 (or is nearly
two octaves below the "great A" of Fraunhofer).

So far, it appears only that we have been measuring _heat_, but I
have called the curve that of solar "energy," because by a series of
independent investigations, not here given, the selective absorption
of the silver, the speculum-metal, the glass, and the lamp-black
(the latter used on the bolometer-strip), forming the agents of
investigation, has been separately allowed for. My study of lamp-black
absorption, I should add in qualification, is not quite complete. I have
found it quite transparent to certain infra-red rays, and it is very
possible that there may be some faint radiations yet to be discovered
even below those here indicated.

In view of the increased attention that is doubtless soon to be given
to this most interesting but strangely neglected region, and which by
photography and other methods is certain to be fully mapped hereafter, I
can but consider this present work less as a survey than as a sketch of
this great new field, and it is as such only that I here present it.

All that has preceded is subordinate to the main research, on which I
have occupied the past two years at Alleghany, in comparing the spectra
of the sun at high and low altitudes, but which I must here touch upon
briefly. By the generosity of a friend of the Alleghany Observatory, and
by the aid of Gen. Hazen, Chief Signal Officer of the U S. Army, I was
enabled last year to organize an expedition to Mount Whitney in South
California, where the most important of these latter observations were
repeated at an altitude of 13,000 feet. Upon my return I made a special
investigation upon the selective absorption of the sun's atmosphere,
with results which I can now only allude to.

By such observations, but by methods too elaborate for present
description, we can pass from the curve of energy actually observed to
that which would be seen if the observer were stationed wholly above the
earth's atmosphere, and freed from the effect of its absorption.

The salient and remarkable result is the growth of the blue end of the
spectrum, and I would remark that, while it has been long known from
the researches of Lockyer, Crova, and others that certain rays of short
wave-length were more absorbed than those of long, these charts show
_how much_ separate each ray of the spectrum has grown, and bring, what
seems to me, conclusive evidence of the shifting of the point of maximum
energy without the atmosphere toward the blue. Contrary to the accepted
belief, it appears here also that the absorption on the whole grows less
and less, to the extreme infra-red extremity; and on the other hand,
that the energy before absorption was so enormously greater in the blue
and violet, that the sun must have a decidedly bluish tint to the naked
eye, if we could rise above the earth's atmosphere to view it.

But even were we placed outside the earth's atmosphere, that surrounding
the sun itself would still remain, and exert absorption. By special
methods, not here detailed, we have at Alleghany compared the
absorption, at various depths, of the sun's own atmosphere for each
spectral ray, and are hence enabled to show, with approximate truth, I
think for the first time, the original distribution of energy throughout
the visible and invisible spectrum at the fount of that energy, in the
sun itself. There is a surprising similarity, you will notice, in the
character of the solar and telluric absorptions, and one which we could
hardly have anticipated _a priori_.

Here, too, violet has been absorbed enormously more than the green, and
the green than the red, and so on, the difference being so great, that
if we were to calculate the thickness of the solar atmosphere on the
hypothesis of a uniform transmission, we should obtain a very thick
atmosphere from the rate of absorption in the infra-red alone, and a
very thin one from that in the violet alone.

But the main result seems to be still this, that as we have seen in the
earth's atmosphere, so we see in the sun's, an enormous and progressive
increase of the energy toward the shorter wave-lengths. This conclusion,
which, I may be permitted to remark, I anticipated in a communication
published in the _Comptes Rendus_ of the Institute of France as long
since as 1875, is now fully confirmed, and I may mention that it is so
also by direct photometric methods, not here given.

If, then, we ask how the solar photosphere would appear to the eye,
could we see it without absorption, these figures appear to show
conclusively that it would be _blue_. Not to rely on any assumption,
however, we have, by various methods at Allegheny, reproduced this
color.

Thus (to indicate roughly the principle used), taking three Maxwell's
disks, a red, green, and blue, so as to reproduce white, we note the
three corresponding ordinates at the earth's surface spectrum, and,
comparing these with the same ordinates in the curve giving the energy
at the solar surface, we rearrange the disks, so as to give the
proportion of red, green, and blue which would be seen _there_, and
obtain by their revolution a tint which must approximately represent
that at the photosphere, and which is most similar to that of a blue
near Fraunhofer's "F."

The conclusion, then, is that, while all radiations emanate from the
solar surface, including red and infra-red, in greater degree than we
receive them, the blue end is so enormously greater in proportion that
the proper color of the sun, as seen at the photosphere is blue--not
only "bluish," but positively and distinctly blue; a statement which I
have not ventured to make from any conjecture, or on any less cause than
on the sole ground of long continued experiments, which, commenced some
seven years since, have within the past two years irresistibly tended to
the present conclusion.

The mass of observations on which it rests must be reserved for more
detailed publication elsewhere. At present, I can only thank the
association for the courtesy which has given me the much prized
opportunity of laying before them this indication of methods and
results.

* * * * *

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

[Footnote: Continued from SUPPLEMENTS 244 and 246.]

By NELSON H. DABTON.

PART III.

Hoboken.--The locality represented here is where the same serpentine
that we met on Staten Island crops out, and is known as Castle Hill. It
is a prominent object in view when on the Hudson River, lying on Castle
Point just above the Stevens Institute and about a mile north of the
ferry from Barclay or Christopher Street, New York city. Upon it is the
Stevens estate, etc., which is ordinarily inaccessible, but below this
and along the river walk, commencing at Fifth Street and to Twelfth,
there is an almost uninterrupted outcrop from two to thirty feet in
thickness and plentifully interspersed with the veins of the minerals
of the locality, which are very similar to those of Staten Island; the
serpentine, however, presenting quite a different appearance, being of a
denser and more homogeneous structure and color, and not so brittle or
light colored as that of Staten Island, but of a pure green color. The
veins of minerals are about a half an inch to--in the case of druses
of magnesite, which penetrate the rock in all proportions and
directions--even six inches in thickness. They lie generally in a
perpendicular position, but are frequently bent and contorted in every
direction. They are the more abundant where the rock is soft, as veins,
but included minerals are more plentiful in the harder rock. There is
hardly any one point on the outcrop that may be said to be favored in
abundance, but the veins of the brucites, dolomite, and magnesites are
scattered at regular and short intervals, except perhaps the last, which
is most plentiful at the north end of the walk.

_Magnesite_.--This mineral, of which we obtained some fine specimens on
Staten Island, occurs extremely plentifully here, constituting five or
six per cent. of a large proportion of the rock, and in every imaginable
condition, from a smooth, even, dark colored mass apparently devoid of
crystalline form, to druses of very small but beautiful crystals, which
are obtained by selecting a vein with an opening say from a quarter to a
half-inch between it and one or, if possible, both points of its contact
with the inclosing rock, and cutting away the massive magnesite and rock
around it, when fine druses and masses or geodes may be generally found
and carefully cut out. The crystals are generally less than a quarter of
an inch long, and the selection of a cabinet specimen should be based
more upon their form of aggregation that the size of the crystals.
Nearly all the veins hold more or less of these masses through their
total extent, but many have been removed, and consequently a careful
search over the veins for the above indications, of which there are
still plenty undeveloped or but partly so, would well repay an hour
or more of cutting into, by the specimens obtained. Patience is an
excellent and very necessary virtue in searching for pockets of
minerals, and is even more necessary here among the multitudinous barren
veins. One hint I might add, which is of final importance, and the
ignorance of which has so far preserved this old locality from
exhaustion, is that every specimen of this kind in the serpentine, of
any great uniqueness, is to be found within five feet from the upper or
surface end of the vein, which in this locality is inaccessible in the
more favored parts without a ladder or similar arrangement upon which
one may work to reach them. Here the veins will be found to be very far
disintegrated and cavernous, thus possessing the requisite conditions of
occurrence (this is also true of Staten Island, but there more or less
inaccessible) for this mineral and similar ones that occur in geodes or
drused incrustations, while it is just _vice versa_ for those occurring
in closely packed veins, as brucite, soapstone, asbestos, etc., where
they occur in finer specimens, where they are the more compact, which is
deep underground. This is also partly true of the zeolites and granular
limestone species with included minerals. I do not think there is any
rule, at least I have not observed it in an extended mineralogical
experience; but if they favor any part, it is undoubtedly the top, as
in the granular limestone and granite; however, they generally fall
subordinate to the first principle, as they more frequently, in this
formation, with the exception of chromic iron, occur not in the
serpentine but in the veins therein contained; for instance, crystals
of dolomite are found deeper in the rock as they occur in the denser
soapstone, which becomes so at a more or less considerable depth, with
spinel, zircon, etc., of the granular limestone. They occur generally in
pockets within five feat from the surface, but they can hardly be called
included minerals, as they are rather, as their mention suggests,
pockets, and adjacent or in contact with the intruded granite or
metamorphosed rock joining the formation at this point. This is
seemingly at variance when we consider datholite, but when we do find it
in pockets a hundred and fifty feet below the surface, in the Weehawken
tunnel, it is not in the trap, but on the surface of what was a cleft
or empty vein, since filled up with chlorite extending from the surface
down, while natrolite, etc., by the trap having clefts of such variable
and often great depth, allowed the solution of the portion thus
contributed that infiltered from the surface easy access to the beds
in which they lie, the mode of access being since filled with densely
packed calcite, which was present in over-abundance. This is not
applicable to serpentine, as the clefts are never of any great depth,
and the five feet before mentioned are a proportionately great depth
from the surface. As I mentioned in commencing this paper (Part I),
every part of the success of a trip lies in knowing where to find the
minerals sought; and by close observation of these relations much more
direction may be obtained than by my trying to describe the exact point
in a locality where I have obtained them or seen them. There is much
more satisfaction in finding rich pockets independently of direction,
and by close observance of indications rather than chance, or by having
them pointed out; for the one that reads this, and goes ahead of you to
the spot, and either destroys the remainder by promiscuous cuttings, or
carries them off in bulk, as there are many who go to a locality, and
what they cannot carry off they destroy, give you a disappointment in
finding nothing; consequently, I have considered that this digression
from our subject in detail was pardonable, that one may be independent
of the stated parts of the locality, and not too confidently rely on
them, as I am sometimes disappointed myself in localities and pockets
that I discover in spare time by finding that some one has been there
between times, and carried off the remainder. The characteristics of
magnesite I have detailed under that head under Pavilion Hill, Staten
Island; but it may be well to repeat them briefly here. Form as above
described, from a white to darker dirty color. Specific gravity, 2.8-3;
hardness, about 3.5. Before the blowpipe it is infusible, _and not
reduced to quicklime_, which distinguishes it from dolomite, which it
frequently resembles in the latter's massive form, common here in veins.
It dissolves in acid readily with but little effervescence, which
little, however, distinguishes it from brucite, which it sometimes
resembles and which has a much lower-specific gravity when pure.

_Dolomite_.--This mineral has been very common in this locality.
It differs, perhaps, as I have before explained, from magnesite in
containing lime besides magnesia, and from calc spar by the _vice
versa_. Much of the magnesite in this serpentine contains more or less
lime, and is consequently in places almost pure dolomite, although
crystals are seldom to be found in this outcrop, it all occurring as
veins about a half-inch thick and resembling somewhat the gurhofite
of Staten Island, only that it is softer and less homogeneous in
appearance. Its color is slightly tinged green, and specimens of it are
not peculiarly unique, but perhaps worth removing. Its characteristics
are: first, its burning to quicklime before the blowpipe, distinguishing
it from pure magnesite; second, its slow effervescence in acids. Besides
these, its specific gravity is 2.8, hardness, 8.5; from calcspar it
cannot be distinguished except by chemical analysis, as the two species
blend almost completely with every intermediate stage of composition
into either calc spar, or, what occurs in this locality, aragonite,
similar in composition to it, or dolomite. The color of the last,
however, is generally darker, and it cleaves less readily into its
crystalline form, which is similar to calc spar, and of which it is
harder, 3.5 to 3 of calc spar.

_Aragonite_.--This mineral, identical in composition with calc spar, but
whose crystalline form is entirely different, occurs in this locality in
veins hardly recognizable from the magnesite or dolomite, and running
into dolomite. It is not abundant, and the veins are limited in extent;
the only distinguishment it has from the dolomite, practically, is its
fibrous structure, the fibers being brittle and very coarse. If examined
with a powerful glass, they will be seen to be made up of modified long
prisms. The specific gravity is over 2.9, hardness about 4, unless much
weathered, when it becomes apparently less. There are some small veins
at the north end of the walk, and in them excellent forms may be found
by cutting into the veins.

_Brucite_.--This mineral occurs here in fair abundance, it being one of
the principal localities for it in the United States, and where formerly
extremely unique specimens were to be obtained. It has been pretty well
exhausted, however, and the fine specimens are only to be obtained by
digging into the veins of it in the rock, which are quite abundant on
the south end of the walk, and, as I before noted, as deep as possible
from the top of the veins, as it is a closely packed mineral not
occurring in geodes, druses, etc. Two forms of it occur; the one,
nemalite, is in fibers of a white to brown color resembling asbestos,
but the fibers are brittle, and hardly as fine as a typical asbestos. It
is packed in masses resembling the brucite, from which it only differs
in breaking into fibers instead of plates, as I have explained in my
description of that species (see Part II). They are both readily soluble
in acids, with effervescence, and infusible but crumble to powder before
the blowpipe, or at least become brittle; when rubbed in mass with a
piece of iron, they phosphoresce with a yellow light; specific gravity,
2.4, hardness, 1.5 to 2. Its ready solubility in acids without
effervescence at once distinguishes it from any mineral that it may
resemble. The specimens of nemalite may be more readily obtained than
the brucite but fine specimens of both may be obtained after finding a
vein of it, by cutting away the rock, which is not hard to do, as it
is in layers and masses packed together, and which maybe wedged out in
large masses at a time with the cold chisel and hammer, perhaps at the
rate of three or four cubic feet an hour for the first hour, and in
rapidly decreasing rate as progress is made toward the unweathered rock
and untouched brucite, etc.

_Serpentine_.--Fair specimens of this may be obtained of a dark oil
green color, but not translucent or peculiarly perfect forms. The
variety known as marmolite, which splits into thin leaves, is plentiful
and often well worth removing.

_Chromic Iron_.--Crystals of this are included in the denser rock
in great abundance; they are very small, seldom over a few lines
in diameter, of an iron black color, of a regular octahedral form;
sometimes large crystals may be found in place or in the disintegrated
loose rock. I have seen them a half inch in diameter, and a half dozen
in a small mass, thus forming an excellent cabinet specimen. By finding
out by observation where they are the thickest in the rock, and cutting
in at this point, more or less fine crystals may be obtained. This is
readily found where they are so very abundant, near the equidistant
points of the walk, that no difficulty should be encountered in so
doing. These characteristics are interesting, and if large specimens
cannot be obtained, any quantity of the small crystals may be split out,
and, as a group, used for a representative at least. Before the blowpipe
it is infusible, but if powdered, it slowly dissolves in the molten
borax bead and yields a beautiful green globule. The specific gravity,
which is generally unattainable, is about 4.5, and hardness 5 to 6. Its
powder or small fragments are attracted by the magnet. A few small veins
of this mineral are also to be found horizontally in the rock, and
small masses may be obtained. They are very rare, however. I have seen
numerous agates from this locality, but have not found them there
myself. They may be looked for in the loose earth over the outcrop, or
along the wall of the river. Our next locality is Paterson, N. J., or
rather in a trip first to West Paterson by the D.L. & W. Railroad,
Boonton branch, then back to Paterson proper, which is but a short
distance, and then home by the Erie road, or, if an excursion ticket has
been bought, on the D.L. & W, back from West Paterson. Garret Rock holds
the minerals of Paterson, and although they are few in number, are very
unique. The first is phrenite. This beautiful mineral occurs in
geodes, or veins of them, near the surface of the basalt, which is the
characteristic formation here, and lies on the red sandstone.

These veins are but two or three feet from the surface, and the ones
from which the fine specimens are to be and have been obtained are
exposed by the railroad cutting about a thousand feet north of the
station at West Paterson, and on the west side of the rails. Near or
below the beds is a small pile of debris, prominent by being the only
one in the vicinity near the rails. In this loose rock and the veins
which are by this description readily found and identified, they are
about three inches in thickness, and in some places widen out into
pockets even a foot in diameter They look like seams of a dark earth,
with blotches of white or green matter where they are weathered, but are
fresher in appearance inside. The rock, in the immediate vicinity of the
veins, is soft, and may be readily broken out with the hammer of, if
possible, a pick bar, and thus some of these geode cavities broken into,
and much finer specimens obtained than in the vein proper. Considerable
occurs scattered about in the before-mentioned pile of loose rock and
debris, and if one does not prize it sufficiently to cut into the rock,
taking the chances of lucky find, plenty may be obtained thus; but as
it has been pretty thoroughly picked over where loose, it is much more
satisfactory to obtain the fine specimens in place in the rock. When
the bed for the railroad was being cut here, many fine specimens were
obtained by those in the vicinity, and the natives of the place have it
in abundance, and it may be obtained from many of them for a trifle, if
one is not inclined to work it out. The mineral itself occurs in masses
in the vein of a white, greenish white, or more or less dark green
color. Sometimes yellowish crystals of it occur plentifully in short
thick prisms, but the common form is that of round coralloid bunches,
having a radiated structure within. Sometimes it is in masses made up
of a structure resembling the leaves of a book slightly opened, and in
nearly every shape and size. Crystals of the various forms may be well
secured, and also the different colors from the deep green to the blue
white, always remembering that true, perfect crystals are of more value
than masses or attempted forms. The specific gravity is 2.8 to
2.9, hardness nearly 7 before the blowpipe; it readily fuses after
intumescing; it dissolves in hot acid without gelatinizing, leaving a
flaky residue.

_Datholite_.--This mineral is very abundant as inferior specimens, and
frequently very fine ones may be obtained. They occur all around Garret
Rock at the juncture of the basalt and red sandstone, in pockets, and as
heavy druses. They are most abundant near the rock cuttings between West
Paterson and Paterson, and may be cut out by patient labor. This is a
long known and somewhat noted locality for datholite, and no difficulty
need be experienced in obtaining plenty of fair specimens. Near them is
the red sandstone, lying under the basalt, and baked to a scoriaceous
cinder. Upon this is a layer of datholite in the form of a crystalline
plate, and over or above this, either in the basalt or hanging down into
cavities in the sandstone, are the crystals or geodes of datholite. Old
spots are generally exhausted, and consequently every new comer has to
hunt up new pockets, but as this is readily done, I will not expend
further comment on the matter. The datholite, as in other localities,
consists of groups of small colorless crystals. Hardness, about 5;
specific gravity, 3. Before the blowpipe it intumesces and melts to a
glassy globule coloring the flame green, and forms a jelly when boiled
with the acids.

_Pectolite_--This mineral is also quite abundant in places, the greater
part occurring with or near the phrenite before mentioned, in small
masses generally more or less weathered, but in very fair specimens,
which are about an inch in thickness. It is readily recognized by its
peculiar appearance, which, I may again repeat, is in fibrous masses,
these fibers being set together in radiated forms, and are quite tough
and flexible, of a white color, and readily fused to a globule before
the blowpipe.

_Feldspar_.--This mineral occurs strewn over the hill from place to
place, and is peculiarly characterized by its lively flesh red color,
quite different from the dull yellowish gray of that from Staten Island
or Bergen Hill. Fine crystals of it are rather rare, but beautiful
specimens of broken groups may be obtained in loose debris around the
hill and in its center. I have not been able to locate the vein or veins
from which it has come, but persistent search will probably reveal it,
or it may be stumbled upon by accident. Some of the residents of the
vicinity have some fine specimens, and it is possible that they can
direct to a plentiful locality. However, some specimens are well worth
a thorough search, and possess considerable value as mineralogieal
specimens. The specific gravity of the mineral is 2.6, and it has a
hardness of 6 before the blowpipe. It is with difficulty fused to a
globule, more or less transparent. It occurs undoubtedly in veins in the
basalt and near the surface of the outcrop As this locality has never
before been mentioned as affording this species, it is fresh to the
amateur and other mineralogists, and there need be no difficulty in
obtaining some fine specimens. Its brilliant color distinguishes it from
other minerals of the locality.

It is possible that some of the other zeolites as mentioned under Bergen
Hill occur here, but I have not been able to find them. The reason
may be that the rock is but little cut into, and consequently no new
unaltered veins are exposed.

COPPER MINES, ARLINGTON, N. J.--A short distance north of this station,
on the New York and Greenwood Lake Railroad, and about nine miles from
Jersey City, is one of the cuttings into the deposits of copper which
permeate many portions of the red sandstone of this and the allied
districts in Connecticut and Massachusetts, and which have been so
extensively worked further south at Somerville and New Brunswick, etc.
There are quite a variety of copper minerals occurring in these mines,
and as they differ but little in anything but abundance, I will describe
this, the one nearest to New York City, as I promised in commencing
these papers. The locality of this mine may be readily found, as it is
near the old turnpike from Jersey City, along which the water-pipes or
aqueduct, are laid. By taking the road directly opposite to the station
at Arlington, walking north to its end, which is a short distance, then
turning to the left along the road, there crossing and turning north up
the next road joining this, until the turnpike is reached; this is then
followed east for about a quarter-mile, passing occasional heaps in the
road of green earth, until the head of a descent is reached, when we
turn off into the field to the left, and there find the mine near the
heaps of greenish rocks and ore scattered about, a distance from the
station of about a mile and a half through a pleasing country. The
entrance to the mine is to the right of the bank of white earth on the
edge of, and in the east side of the hill; it is a tunnel more or less
caved in, running in under the heaps of rock for some distance. It will
not be necessary, even if it were safe, to venture into the mine, but
all the specimens mentioned below may be obtained from the heaps of ore
and rock outside, and in the outcrops in the east side of the hill, a
little north of the mouth of the tunnel to the mine. The hammer and cold
chisel will be necessary, and about three hours should be allowed to
stay, taking the noon train from New York there, and the 5.09 P.M. train
in return, or the 6.30 A.M. train from the city, and the 1.57 P.M. in
return. This will give ample opportunity for the selection of specimens,
and, if time is left, to visit the water works, etc.

_Green Malachite_.--This is the prominent mineral of the locality, and
is conspicuous by its rich green color on all the rocks and in the
outcrops. Fine specimens of it form excellent cabinet specimens. It
should be in masses of good size, with a silky, divergent, fibrous
structure, quite hard, and of a pure oil green color, for this purpose.
Drused crystals of it are also very beautiful and abundant, but very
minute. As the greater part of it is but a sixteenth or eighth of an
inch in thickness, it may require some searching to secure large masses
a quarter to a half-inch in thickness, but there was considerable, both
in the rock, debris, and outcrop, remaining the last visit I made to the
place a few months ago. The mineral is so characterized by its color and
solubility in acid that a detailed description of it is unnecessary to
serve to distinguish it. Its specific gravity is 4, and hardness about
4. It decrepitates before the blowpipe, but when fused with some borax
in a small hollow on a piece of wood charcoal, gives a globule of
copper. It readily dissolves in acids, with effervescence, as it is a
carbonate of copper.

_Red Oxide of Copper_--This rather rare mineral is found in small
quantities in this mine, or near it, in the debris or outcrop. Perfect
crystals, which are of a dodecahedral or octahedral form, are fairly
abundant. They are difficult to distinguish, as they are generally
coated, or soiled at least, with malachite. The color proper is of
a brownish red, and the hardness about 4, although sometimes, it is
earthy, with an apparent hardness not over 2. The crystals are generally
about a quarter of an inch to a half of an inch in diameter, and found
inside the masses of malachite. When these are broken open, the red
copper oxide is readily distinguished, and may be separated or brought
into relief by carefully trimming away the malachite surrounding it as
its gravity (6) is much greater than malachite. When a piece of the last
is found which has a high gravity, it may be suspected and broken into,
as this species is much more valuable and rarer than the malachite
which is so abundant. It dissolves in acids like malachite, but without
effervescence, if it be freed from that mineral, and acts the same
before the blowpipe. Sometimes it may be found as an earthy substance,
but is difficult to distinguish from the red sandstone accompanyit,
which both varieties resemble, but which, not being soluble in the
acids, find having the blowpipe reactions, is thus characterized. This
red oxide of copper does not form a particularly showy cabinet specimen,
but its rarity and value fully compensate for a search after it. I have
found considerable of it here, and seen some little of it in place
remaining.

_Chrysorolla_.--This mineral, very abundant in this locality, resembles
malachite, but has a much bluer, lighter color, without the fibrous
structure so often present in malachite, and seldom in masses, it only
occurring as light druses and incrustations, some of which are very
beautiful, and make very fine cabinet specimens. Its hardness is less
than that of the other species, being under 3, and a specific gravity
of only 2, but as it frequently occurs mixed with them, is difficult to
distinguish. It does not dissolve in nitric acid, although that takes
the characteristic green color of a solution of nitrate of copper,
as from malachite or red oxide. This species is found all over this
locality, and a fine drused mass of it will form an excellent memento of
the trip.

_Copper Glance_.--This mineral is quite abundant in places here, but
fine crystals, even small, as it all is, are rare. That which I have
seen has been embedded in the loose rock above the mine, about a quarter
inch in diameter, and more or less disguised by a green coating of
chrysocolla. The color of the mineral itself is a glistening grayish
lead color, resembling chromite somewhat in appearance, but the crystals
of an entirely different shape, being highly modified or indistinct
rhombic prisms. The specific gravity is over 5, and the hardness 4.
Before the blowpipe on a piece of wood charcoal it gives off fumes of
sulphur, fuses, boils, and finally leaves a globule of copper. In nitric
acid it dissolves, but the sulphur in combination with it separates as
a white powder. A steel knife blade placed in this solution receives a
coating of copper known by its red color.

_Erubescite_--This mineral occurs massive in the rock here with the
other copper minerals, and is of a yellowish red color, more or less
tarnished to a light brown on its surface, Before the blowpipe on
charcoal it fuses, burns, and affords a globule of copper and iron,
which is attracted by the magnet. Its specific gravity is 5, hardness
3. It resembles somewhat the red oxide, but the low gravity, inferior
hardness, lighter color, and blowpipe reaction distinguish it. These
are the only copper minerals likely to be found at this mine, and the
following table and note will show their characteristics:

Name. Speci- Hardness Action of Action of Color. Form.
fic Blowpipe Heat. Hot Nitric
Gravity. Acid.

Mala- From 4 From 3 Decrepitates, Dissolves Pure Oil Fibrous,
chite to 4.5 to 4 but fuses with with Green. massive,
borax to a effer- or in-
green bead. vescence crusting.

Red 6 From 3.5 On charcoal Dissolves A deep Modified
Oxide to 4 yields a without brownish crystals.
globule of effer- red.
copper. vescence

Chryso- From 2 From 2 Infusible. Partly Bright Incrus-
colla to 2.3 to 3 soluble bluish tations.
green.

Copper 5 From 2.5 Fumes of Copper Grayish Modified
Glance to 3 sulphur and a soluble, Lead. rhombic
globule of sulphur prisms.
copper deposits

Erube- 5 From 3 Fumes of Partly Yellowish Massive.
scite to 3.5 sulphur and soluble red or
magnetic tarnished.
globule.

Malachite is characterized by its color from Copper Glance and Red Oxide
and Erubescite, and from Chrysocolla by the action of the acid, the
fibrous structure and blowpipe reaction, gravity, and hardness.

Red Oxide is distinguished from Erubescite, which it alone resembles,
by its darker color, higher specific gravity, and yielding a globule of
pure copper.

Chrysocolla is characterized by its low specific gravity, light color,
lack of fibrous structure, blowpipe reactions, and the acid.

Copper Glance is distinguished by its color, fumes of sulphur, and
globule of copper.

Erubescite is distinguished from Red Oxide, which it alone resembles, by
its lighter color, great solubility when pure, and yielding a magnetic
globule before the blowpipe in the hollow of a piece of wood charcoal,
which is used instead of platinum wire in this investigation.

* * * * *

ENTOMOLOGY.

[Footnote: From the _American Naturalist_, November, 1882.]

THE BUCKEYE LEAF STEM BORER.--In our account of the proceedings of the
entomological sub-section of the A.A.A.S., at the 1881 meeting (see
_American Naturalist_, 1881, p. 1009), we gave a short abstract of Mr.
E.W. Claypole's paper on the above insect, accepting the determination
of the species as _Sericoris instrutana_, and mentioning the fact that
the work of _Proteoteras aesculana_ Riley upon maple and buckeye was very
similar. A letter recently received from Mr. Claypole, prior to sending
his article to press, and some specimens which be had kindly submitted
to us, permit of some corrections and definite statements. We have a
single specimen in our collection, bred from a larva found feeding, in
1873, on the blossoms of buckeye, and identical with Mr. Claypole's
specimens, which are in too poor condition for description or positive
determination. With this material and with Mr Claypole's observations
and our own notes, the following facts are established:

1st. We have _Proteoteras aesculana_ boring in the terminal green twigs
of both maple and buckeye, in Missouri, and often producing a swelling
or pseudo-gall. Exceptionally it works in the leaf-stalk. It also feeds
on the samara of maple, as we reared the moth in June, 1881, from
larvae infesting these winged seeds that had been collected by Mr. A.J.
Wethersby, of Cincinnati, O.

2d. We have an allied species, boring in the leaf-stalk of buckeye,
in Ohio, as observed by Mr. Claypole. It bears some resemblance
to _Proteoteras aesculana_, but differs from it in the following
particulars, so far as can be ascertained from the poor material
examined: The primaries are shorter and more acuminate at apex.
Their general color is paler, with the dark markings less distinctly
separated. No distinct tufts of scales or knobs appear, and the
ocellated region is traversed by four or five dark longitudinal lines.
It would be difficult to distinguish it from a rubbed and faded specimen
of _aesculana_, were it not for the form of the wing, on which, however,
one dare not count too confidently. It probably belongs to the same
genus, and we would propose for it the name of _claypoleana_. The
larva is distinguished from that of _aesculana_ by having the minute
granulations of the skin smooth, whereas in the latter each granule has
a minute sharp point.

3d. _Sericoris instrutana_ is a totally different insect. Hence our
previous remarks as to the diversity of food-habit in this species have
no force--_C.V.R._

* * * * *

DEFOLIATION OF OAK TREES BY DRYOCAMPA SENATORIA IN PERRY COUNTY,
PA.--During the present autumn the woods and road-sides in this
neighborhood (New Bloomfield) present a singular appearance in
consequence of the ravages of the black and yellow larva of the above
species. It is more abundant, so I am informed, than it has ever been
before. In some places hardly any trees of the two species to which its
attack is here limited have escaped. These are the black or yellow oak
(_Q. tinctoria_) with its variety (_coccinea_), the scarlet oak and, the
scrub oak (_Q. ilicifolia_). These trees appear brown on the hill-sides
from a distance, in consequence of being altogether stripped of
their leaves. The sound of the falling frass from the thousands of
caterpillars resembles a shower of rain. They crawl in thousands over
the ground, ten or twelve being sometimes seen on a square yard. The
springs and pools are crowded with drowned specimens. They are equally
abundant in all parts of the county which I have visited during the
past week or two--the central and southeastern.--_E. W. Olaypole, New
Bloomfield, Pa_.

* * * * *

EFFICACY OF CHALCID EGG-PARASITES.--Egg-parasites are among the most
efficient destroyers of insects injurious to vegetation, since they kill
their victim before it has begun to do any damage; but few persons are
aware of the vast numbers in which these tiny parasites occasionally
appear. Owing to the abundance of one of them (_Trichogramma pretiosa_
Riley), we have known the last brood of the cotton-worm to be
annihilated, and Mr. H.G. Hubbard reported the same experience at
Centerville, Fla. Miss Mary E. Murtfeldt has recently communicated to us
a similar experience with a species of the Proctotrupid genus Telenomus,
infesting the eggs of the notorious squash-bug (_Coreus tristis_). She
writes: "The eggs of the Coreus have been very abundant on our squash
and melon vines, but fully ninety per cent. of them thus far [August 2]
have been parasitized--the only thing that has saved the plants from
utter destruction."

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