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

V >> Various >> Scientific American Supplement, No. 363, December 16, 1882

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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manner, or the solution may be withdrawn from each cell by a siphon.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.

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