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

V >> Various >> Scientific American Supplement, No. 362, December 9, 1882

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

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

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

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

* * * * *

[AMERICAN POTTERY AND GLASSWARE REPORTER.]

ALUMINUM--ITS PROPERTIES, COST, AND USES.

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

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

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

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

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

Aluminum is derived from the oxide alumina, which is the principal
constituent of common clay. Lavoissier, a celebrated French chemist,
first suggested the existence of the metallic bases of the earths and
alkalies, which fact was demonstrated twenty years thereafter by
Sir Humphry Davy, by eliminating potassium and sodium from their
combinations; and afterward by the discovery of the metallic bases of
baryta, strontium, and lime. The earth alumina resisting the action of
the voltaic pile and the other agents then used to induce decomposition,
twenty years more passed before the chloride was obtained by Oerstadt,
by subjecting alumina to the action of potassium in a crucible heated
over a spirit lamp. The discovery of aluminum was at last made by Wohler
in 1827, who succeeded in 1846 in obtaining minute globules or beads
of this metal by heating a mixture of chloride of alumina and sodium.
Deville afterward conducted some experiments in obtaining this metal at
the expense of Napoleon III., who subscribed L1,500, and was rewarded by
the presentation of two bars of aluminum. The process of manufacture was
afterward so simplified that in 1857 its price at Paris was about two
dollars an ounce. It was at first manufactured from common clay, which
contains about one-fourth its weight of aluminum, but in 1855 Rose
announced to the scientific world that it could be obtained from a
material called "cryolite," found in Greenland in large quantities,
imported into Germany under the name of "mineral soda," and used as a
washing soda and in the manufacture of soap. It consists of a double
fluoride of aluminum, and only requires to be mixed with an excess of
sodium and heated, when the mineral aluminum at once separates. Its cost
of manufacture is given in this estimate for one pound of metal: 16 lb.
of cryolite at 8 cents per pound, $1.28: 21/2 lb. metallic sodium at about
26 cents per pound, 70 cents; flux and cost of reduction, $2.02; total,
$4.

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

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

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

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

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

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

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

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

* * * * *

DETERMINATION OF POTASSA IN MANURES.

By M.E. DREYFUS.

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

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

* * * * *

THE ORIGIN AND RELATIONS OF THE CARBON MINERALS.

[Footnote: Read before the New York Academy of Sciences, February 6,
1882.]

By J.S. NEWBERRY.

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

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

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

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

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

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

[Illustration: DIAGRAM SHOWING THE GENETIC RELATIONS OF THE CARBON
MINERALS.]

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

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

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

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

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

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

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

RESIDUAL PRODUCTS.

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

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

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

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

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

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

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