Wilfrid Richmond.

The Americana: a universal reference library, comprising the arts ..., Volume 10 online

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which are called black, sour, cotton-gum, etc.
(see Tupelo) ; (3) the liquid amber (q.v.).

Gumbinnen, goom-bin'nen, Prussia, the
capital of a government with an area of 6,125
square miles. The town is on the Pissa, 22
miles by rail southwest of Edytkuhnen on the
Russian frontier. It is comparatively modern,
its municipal charter dating from 1722. There
are manufactures of woolens and linens, and a
trade in cattle and agricultural produce, Pop.
about 15,000.

Gumbo. See Hibiscus; Okra.

Gumma, gum 'a, a tumorous deposit that
occurs in the tertiary stage of syphilis (q.v.).
It affects most frequently the bones, cartilages,
skin, and periosteum. They are made up of a
hard connective tissue which tends to undergo
softening, causing destruction of the part and
deep ulceration if near the surface. The peri-
osteum of the cranial bones is particularly lia-
ble to be affected, causing dangerous pressure
on the brain.

Gumming, or Gumosis. See Diseases op
Plants.

Gums, various mucilaginous substances,
generally obtainable^ from the sap of trees. They
are soluble either in cold water or in alcohol.
Many aromatic products such as are employed
in making perfumes and incense are to be
classed as gums. Gum Arabic is the best
known among such products. It is obtained
from the Senegal Acacia in Western Africa.
There are no less than eight or nine varieties
of this gum. Gum tragacanth comes from the
Astragalus gummifer, in Western Asia. Cher-
ry-tree gum, whose name tells its origin, is used
for stiffening felt, as in hat making. There are
some gums which might perhaps more properly
be classed as resins, and are sometimes styled
gum-resins ; many of which are used in medicine.

Gun, a strongly-constructed metal tube,
from which destructive projectiles are expelled
by the gradually increasing pressure of gas,
evolved from fired gunpowder or other ex-
plosive. The term comprehends every descrip-
tion of firearm, from cannons, mortars, and
other heavy pieces of ordnance, to the fowling-
piece, rifle, and pocket-pistol. See Arms; Ar-
tillery; Fire-arms; Ordnance.

Gunboat, a term originally applied to
small craft mounting usually a single gun, and
employed exclusively in the defense of coasts
and rivers. Experiences in the Crimean war
suggested the extension of the use of gunboats
to offensive warfare. One of the main objects
of a ship of war being to carry guns, it was
thought that a vessel large enough to carry only a
single gun of the largest size would, from the
rapidity with which it could be manoeuvred, and
its comparative immunity from shot, have great
advantages in attack against large vessels carry-
ing a heavy armament, and requiring much room
and time to manoeuvre. About i860 the British
government constructed about 200 gunboats upon
this principle. They were about 100 feet long
with 22 feet beam, and a draught at load-line of
dy 2 feet. Each was armed with one deck-gun
a 68-pounder, which, by turning on a pivot, couk*



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GUN-CARRIAGE — GUNCOTTON



be used either ahead, astern, or in any other
direction; while the facility of manoeuvring was
further enhanced by the rapidity with which the
vessel itself could be turned almost in her own
length. Experience soon proved that there were
serious defects in this species of armament.
One of these was, that from being obliged to
carry their guns constantly on deck the gun-
boats were liable to be top-heavy and untrust-
worthy in a heavy sea.

A new gunboat was designed in England in
1868 by G. Rendel, the chief peculiarity of which
was the placing of the gun on a platform, which
could be raised to the deck or lowered to the
hold by a donkey-engine. The gun did not turn
on a pivot, the manoeuvring being effected en-
tirely by the turning of the vessel, to effect
which it was fitted with twin-screws worked by
independent engines. Other types of gunboat
have since been constructed for the British navy.
One of a recent and powerful type is 165 feet
in length, with a breadth of 31 feet, and a dis-
placement of 805 tons. It draws 11 feet 7^
inches of water, and has triple-expansion en-
gines, working up to 1,200 horse-power, with a
speed of 13 knots an hour. It carries six 4-inch
steel breech-loading guns, besides two quick-
firing guns and machine-guns, and is bark-
rigged. A number of what are known as tor-
pedo gunboats have been constructed for the
British navy. One boat of this class is 200 feet
in length, with a beam of 23 feet, and a depth
of 13 feet. It is built entirely of steel, has a
torpedo-tube through the bow and another
through the stern in a fore-and-aft line, and
one on each broadside forward, a 4-inch 25-cwt.
central-pivot breech-loading gun, and six
3-pounder, quick-firing guns. It has two sets of
triple-expansion engines, working up to 2,700
horse-power, and enabling the vessel of 450 tons
to steam over 18 knots an hour. Several first-
class gunboats of a more recent type are twin-
screw vessels, 180 feet long, of 700 tons dis-
placement, armed with two 4-inch guns and
four 12-pounder quick-firing guns.

In the United States the gunboat figured to
a very considerable extent in coast and lake
warfare in our first two wars. They were first
used on the Delaware River, in 1775-6, and
drove the British frigate Reliance out of the
roads. In December 1807 there were 69 of
them in United States service, and the Congress
ordered 188 more built, as an auxiliary to the
embargo declared a few days later, making 257
in all. Improved ordnance has made them
valueless, and they had a bad effect on the
service, but there was strong opinion in their
favor at the time, and they did good service in
the War of 181 2. The theory was that these
movable batteries could act in water where large
vessels could not, could be concentrated against
the latter so as to afford as large an armament,
yet present only a number of small targets,
while their antagonist presented only one large
one; that shots aimed too high would do no
harm to gunboats, but would injure masts and
rigging of frigates ; that loss of rudder and sail-
nig gear, the most crippling of accidents to a
ship, could not happen to the gunboats, propelled
and steered by sweeps; that nearness to the
water level gave the guns more accurate aim;
and that 75 gunboats could be built for the cost
of one 36-gun frigate.



In 1903 the United States navy had 20 of the
ordinary gunboats in commission and about 60
torpedo-boats and destroyers of the gunboat
type. Great Britain in 1902 had 33 torpedo gun-
boats, Germany 3, and France 15. In most
countries the gunboat has been superseded by
modern torpedo-boats and destroyers.

Gun-carriage, or Gun-mounting. See
Artillery; Fortification; Ordnance.

Guticotton is the name originally assigned
to the material produced by Schoenbein, of
Basle, Switzerland, in 1845 by treating cotton
with a mixture of strong nitric and sulphuric
acids. The discovery that starch, woody fibre,
and similar substances give rise to the forma-
tion of highly combustible bodies when acted
upon by concentrated nitric acid is attributed to
Braconnot in 1832, and he styled the bodies so
produced generically xyloidine. Six years later
Pelouze took up this subject and extended his
investigations to the behavior of cotton, paper
and vegetable substances generally, and later
Dumas prepared from paper by this means the
substance which he called nitramidine. No
practical result followed these observations until
the discovery by Schoenbein of the advantages
which followed the use of the acid mixture; a
discovery which was also independently made by
Boettger, of Frankfort, in 1847 and by Knop, of
Hanover, and Taylor, of England, in 1847. The
discovery aroused the liveliest expectations
which were stimulated by the facts that the ex-
plosive was much more powerful than gun-
powder and that when used as a propel Ian t, it
gave little or no smoke. Experiments and tests
were begun shortly after with the new explosive
in Germany, France, Austria, England, Russia,
and the United States with a view of utilizing it
as a substitute for gunpowder in guns. Unfortu-
nately the material, as manufactured, was found
to be not only so irregular in action that it was
likely at any time to burst the piece, but also so
unstable as to give rise to numerous accidents
so that, especially after the serious and, at the
time, inexplicable explosions at Vincennes and
Bouchet in France, and Faversham in England,
the experiments were discontinued except in
Austria, where Baron von Lenk gave the matter
close and long-continued study and came to the
conclusion that the grave defects noted were
not inherent in the material, but were due to
the imperfect and irregular methods of manu-
facture, the failure to purify the cotton before
treatment with the acid, and the failure to

?urify the guncotton and free it completely
rom acids after treatment. Following these
convictions he improved the method of manu-
facture to such an extent that in 1862 the Aus-
trian army had 30 batteries provided with gun-
cotton cartridges made up by twisting the fibre
into yarns which were braided together, but the
spontaneous explosions at the magazine at Sim-
mering in 1862 and at Stein feld in 1865, together
with the fact that the guncotton cartridges still
gave at unexpected times abnormal pressures
led to its further use in Austria being inter-
dicted.

Von Lenk's process of manufacture was pat-
ented in England in 1862 and the Prentice
Brothers began manufacturing under this pro-
cess in 1864. In 1865 Abel patented an improve-
ment of the process which was so successful in
use that it gave guncotton a prominent and



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GUNCOTTON



permanent place among explosive substances,
and this process is followed to-day. The cotton
when treated with the acid is in the fibrous con-
dition which so well characterizes it, and under
the microscope these fibres are seen to be hol-
low so that each is really a capillary or hair-like
tube. Von Lenk had shown that cotton con-
tains not only cellulose as the main component
of its structure but that there were smaller and
variable quantities of other substances naturally
present besides foreign bodies accidentally pres-
ent, and that it was necessary to get the cellu-
lose in a pure and dry condition before treating
it with acid. He, too, with others, had proved
that the purity, strength and proportions of the
acids used and the time and temperature of im-
mersion of the cotton in the acid mixture
affected very materially the character of the
substance produced, while it was essential that
every trace of free acid should be removed from
the product, since a most minute quantity of
sulphuric acid acts continuously and cumula-
tively on the guncotton and causes a progres-
sively increasing rate of decomposition. Yet
von Lenk and all others up to this time pro-
duced the guncotton in the same long staple
form as the cotton from which it was made. It
was evident to Abel's mind that as the dry cot-
ton was immersed in the acid mixture the capil-
lary tubes, of which it was composed, would
suck up the liquid acid and retain it with such
force and in such a manner as to make its re-
moval by wringing, or washing with or in water
or by neutralization with alkalies, extremely
difficult and uncertain, and to remedy this Abel
proposed to pulp the guncotton through which
the fibres would be cut into such short lengths
that the acids could be completely and readily
removed from the interiors of the tubes while
furthermore this pulped material could by mold-
ing and pressure be shaped into any desired
forms and dimensions.

Abel's process for the manufacture of mili-
tary guncotton as carried out at the United
States naval torpedo stations was as follows:
The cotton used was what is known as a cop^ or
weaver's waste, which is the tangled clippings
from the spinning room of a cotton mill; the
thready form of this material being preferred to
the fluffy form of the unworked cotton. This
was first hand-picked to remove the larger for-
eign bodies present and to open out after baling.
It was then boiled in 200-pound lots in caustic
soda solution to remove grease, oils and the in-
crusting substances on the fibres, then wrung
out in a centrifugal wringer and dried in a
heated closet. It was then put through a cot-
ton picker to open up the fibre and remove for-
eign bodies which had been overlooked in the
hand-picking, and was then dried in a second
closet at 225 F. until it contained not over one
half per cent of moisture, when it was stored in
small lots in hermetically sealed metal vessels to
cool. It was then dipped in lots of one pound
each in 150 pounds of acids, consisting of 1
part by weight of nitric acid, 1.5 specific
gravity, to 3 parts by weight of sulphuric
acid, 1.845 specific gravity, contained in a
large iron trough about which* cold water cir-
culated so as to maintain a temperature of
70 F. throughout the dipping. The cotton was
plunged rapidly under the acid, allowed to
remain immersed for 10 minutes, removed to
a shelf above the acid dipping trough, where



it was squeezed to remove the excess of acid,
and then at once transferred to a two-gallon
crock made of acid-proof earthenware. As
transferred to this digestion crock the cot-
ton carried with it from 10 to 12 pounds of the
acid mixture, and by pressing the mass down in
the crock with an iron tool, the cotton was
forced to the bottom and covered with a layer
of the acid mixture which was squeezed from it.
The crock was then covered and placed in a
wooden trough where it was partly surrounded
with cool water, which was kept in constant
circulation, and where it was allowed to remain,
so that the cotton could ^digest the acid, for 24
hours. Then the contents were thrown into a
steel centrifugal wringer by which the greater
part of the acid was removed. The guncotton
was then thrown into a tub holding 800 gallons
of water through which a large stream of water
was continually flowing and in which a large
paddle-wheel was in revolution so as to very
quickly bring the acid guncotton into contact
with so large a volume of cold water as to pre-
vent its becoming heated. The guncotton was
then boiled twice for eight hours each in a dilute
solution of soda, wrung out and washed with
fresh water and put in the pulper. This was an
ordinary a beater, i) ^rag-engine,* or 'Hollander,*
such as is used in the paper-making industry,
and the guncotton, suspended in water, was sub-
jected to the action of the machine for two
days m charges of from 300 to 350 pounds,
where, by the shearing action of the knives, the
fibres were cut into short lengths and the gun-
cotton was reduced to the fineness of cornmeal,
and mixed into a pulp with the water present
This was drawn into a large tank, known as the
poacher, where the powdered guncotton was al-
lowed to. settle and the supernatant water drawn
off. Fresh water was added and, by means of a
revolving paddle in the poacher, the guncotton
was mixed with it and washed by it, and this
washing was repeated six or seven times until
the chemical test of a sample showed that the
acid had been completely removed. Then it
was treated with a solution of lime containing a
small quantity of caustic soda and also of pre-
cipitated chalk, and the mass was ready for
molding.

As shown above the first use to which gun-
cotton was put was as a propellent in guns, and
Abel devised means for making powder grains
from the pulped guncotton, but he soon pointed
out the advantages which it possessed, when
compressed, for use in military and naval mines
and torpedoes and for engineering operations in
times of war, and these are the chief uses to
which it has been put To compress it the alka-
line solution from the poacher, containing the
finely divided guncotton in suspension, was
pumped up to a stuff-chest, which is a cylin-
drical tank containing a vertical shaft armed
with paddle-blades which, by revolving, keeps
the guncotton in suspension. From here, by
means of a wagon, the pulp was run into a
hydraulic press where it was subjected to a
pressure of 100 pounds to the square inch and
thereby molded into blocks. These blocks were
then transferred to another press where they
were subjected to a pressure of from 6,000 to
6,800 pounds to the square inch. As made at
the United States naval torpedo stations the
blocks from the molding press were prismatic,
with the vertical edges chamfered, 2.8 inches in



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GUNNERY



diameter by $ T A to s 1 /* inches high, with a cir-
cular hole l /2 inch in diameter, produced by
a mandrel in the press, running vertically
through the centre of the prism. After final
pressing the blocks were 2.9 inches in diameter
by 2 inches high, the hole remaining practically
unchanged, and they still contained from 12 to
16 per cent of water, though as sent out into the
service as a wet guncotton" they were soaked in
water until they contained 35 per cent. In the
final press by means of steel dies, inscriptions in
letters and figures, such as the place and date
of manufacture and factory lot, were placed
upon each block.

In the fibrous condition guncotton appears
like the cotton from which it is made, but it
has a harsher feel and it becomes electrified by
friction when dry. When dry if rubbed in the
dark it becomes phosphorescent. Under the
microscope by polarized light it exhibits colors,
while cotton is colorless. Pure guncotton is
without odor or taste and is insoluble in water.
The gravimetric density before pulping is 0.1,
after pulping 0.3, and after compression from
1.0 to 1.3, but bv excessive pressure it has been
raised to 1.4. The real specific gravity of gun-
cotton is 1.5. When dry, compressed guncotton
is detonated by inserting a detonator in the hole
in the block and firinsr it. Wet guncotton is
detonated by the detonation of a block of dry
guncotton fired in contact with it. The violence
of the explosion of guncotton when thus de-
tonated is comparable with, if not superior to,
that of nitroglycerin. Dry guncotton may be set
on fire and, when compressed, it burns so slowly
in the open that the fire may be extinguished by
pouring water upon it. Wet guncotton, thor-
oughly saturated with water, can be shaped by a
tool without taking fire or exploding. \n form-
ing the cylindrical and conical charges for the
torpedoes thrown from the pneumatic guns of
the United States steamship Vesuvius at Santi-
ago, the prismatic blocks above described were
sawn with a band saw, turned in a lathe and
cut with chisels as wood is treated, but care
was used to keep the blocks and dust wet
throughout the process.

Pure cotton is composed of cellulose having
a formula which chemists believe to be some
multiple of GHu>0». When it is acted upon
by nitric acid or mixtures of nitric with sul-
phuric acid, under the proper conditions, cellu-
lose nitrates are produced through, it is be-
lieved, the replacement of hydrogen atoms m
the molecule by NO* groups^ thus forming
esters or organic salts. Views differ as to the
number of cellulose nitrates existing but, fol-
lowing Vieille, who is the most widely accepted
authority on this point, taking the formula of
cellulose as CmH«0» we may have the follow-
ing:







Percent of


Weight ob-
tained from


Cellulose Nitrates


Nitrogen


100 parts of
Cellulose








Cellulose


endecanitrate . .


U-47


176.4


Cellulose


decanitrate. . . .


12.7$


169.4


Cellulose


enneanitrate . . .


11.96


1 6a. s


Cellulose


octonitrate....


1z.11


148.6


Cellulose


hcptanitrate. . .


10.18


Cellulose


hcxanitrate. . . .


8.0a


141.7


Cellulose


pentanitrate. . .


134-7
127.8


Cellulose


tetranitrate....


6.7*



There are probably existing also isomers of
many of the nitrates given in the table. Follow-
ing their differences in composition these differ-
ent cellulose nitrates have different properties
especially as regards their solubility in organic
solvents. Thus all except the endecanitrate, if
properly made, are soluble at ordinary temper-
atures in a mixture of one volume of alcohol
and two volumes of ether. Such cellulose ni-
rates are called Pyroxyline, nitrocotton, soluble
guncotton, and collodion, cotton or guncotton.
The decanitrate is also called pyrocellulose. All
the cellulose nitrates are by some called nitro-
cellulose. The material produced by the Abel
process described above is partly soluble, but
mostly insoluble in the ether-alcohol mixture,
and to this material the name guncotton or bet-
ter military guncotton is applied. In addition to
guncotton, the cellulose nitrates are used in the
manufacture of smokeless powder, explosive gel-
atine, pyroxylin plastics, pyroxylin varnishes,
photographic films and collodion. For smokeless
powders and explosive gelatine the deca- and
enneanitrates are most largely used. For var-
nishes, collodion and photographic films the
octonitrate is generally employed. And the
heptanitrate, which is of low nitration, is pre-
ferred for the pyroxylin plastics. This last
nitrate may be made by dipping one pound of
pure dry cotton or tissue paper in 100 pounds of
a mixture of 66 parts of sulphuric acid, 17 parts
of nitric acid and 17 parts of water, and con-
tinuing the immersion at 30 C. for 20 to 30
minutes. The acid is then wrung out and the
nitrate washed and neutralized. The higher
nitrates are made by using stronger acids, longer
exposures and higher temperatures. In making
pyroxyline varnishes, which are largely used in
coating metals, artificial leather and in water-
proofing, the pyroxylin is dissolved in ethyl
acetate, amyl acetate and similar organic sol-
vents.

Collodion, which is used in surgery, is made
by placing 30 grams of pyroxylin in a suitable
bottle, pouring upon it 750 cubic centimetres of
ether, corking the bottle and allowing the whole
to stand 15 minutes. Two hundred and fifty
cubic centimetres of alcohol are then added and
the bottle shaken until the pyroxylin is dis-
solved. On allowing to stand the solution be-
comes clear, and if poured upon a flesh wound
the solvents evaporate and a continuous film of
pyroxylin is formed which protects the wound
from the air and which also, by contracting as
it dries, brings the edges of the wound together.
Substances such as cantharides, tannic acid and
the like, by which to produce blistering, styptic
and other effects, may be added to the collodion.
See Explosives. Charles E. Munroe,

The Columbian University, IVashington, D. C
Gunnery. — Gunnery is the art and science
of using guns. The principles of ballistics
necessarily play an important part in the
science of gunnery, and it is necessary to have
a practically exact knowledge of the effect of
air resistance upon the motion of projectiles
before satisfactory practical results can be ob-
tained. Fortunately many experimental firings
have been made with this object in view.
Among them may be mentioned the firings with
spherical projectiles by the Metz Commission,
in 18^40, and again in 1856-58; and the names
of Didion and Saint Robert are associated with



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laws deduced from these firings. Other firings
with more modern projectiles were made in
Russia in 186&-9 and in England in 1866-70.
The Krupp firings were made at Essen, Ger-
many, in 1875-^1; and some firings were con-
ducted in Holland in 1884. Firings were made
at Gavre, France, and the results are accessible
in Charbonnier's *Traite de Balistique Ex-
terieure," 1905. Firings at Shoeburyness, Eng-
land, in 1904-6, gave excellent data with regard
to modem projectiles; and the Krupp firm has
made and recorded the results of many firings.

Various practical formulas have been de-
vised as the results became available, and for-
mulas are associated with the names of Didion,
Saint Robert, Mayevski, Hojel, Bash forth,
Zabudski, Siacci, Chapel, Vallier and Scheve.
These formulas presented more or less ac-
curately the resistance of the air in terms of
the velocity, air density and projectile char-
acteristics.

The peculiarities of the law of air resistance
are best shown by considering the fact that
Newton, upon hypotheses not altogether ac-
curate, found that the resistance of the air
varied as the square of the velocity. To show
the effect as actually found in the firings, the
law of air resistance will be placed in the form
(See article Ballistics)



Online LibraryWilfrid RichmondThe Americana: a universal reference library, comprising the arts ..., Volume 10 → online text (page 80 of 185)