G A M 
GAL 
Tt is well known that hydrogen gas, in its 
pascent state, reduces the oxides of metals. 
Accordingly, when the tube, fig. 22 . is filled 
with a solution of acetite of lead in distilled 
water, and a communication is made with the 
battery as above described, no gas is per- 
ceived to issue from the wire which proceeds 
from the negative end of the battery ; but, 
in a few minutes, beautiful metallic needles 
are perceived on the extremity of this wire ; 
these soon increase, and assume the form of 
a fern or other vegetable. The lead thus 
separated is in its perfect metallic state, and 
very brilliant. 
When a solution of sulphat of copper is 
employed, the copper is precipitated in its 
metallic state; but instead of appearing in 
crystals, it forms a kind of button, which ad- 
heres firmly to the end of the wire. 
On making the experiment with a solution 
of nitrate of silver, the silver is precipitated 
in the form of a beautiful metallic brush, the 
metal shooting into line needle-like crystals. 
If iron is immersed in a solution of sulphate 
of copper, the latter metal will be precipi- 
tated in a metallic form, and will adhere to 
the surface of the former. Upon silver mere- 
ly immersed in the same solution, no such 
elfect is produced; but as soon as the two 
metals, viz. the silver and the copper, are 
brought into contact, the silver receives a 
coating of copper. 
Little knowledge has yet been obtained 
concerning the chemical changes taking place 
in the batteries of the second order. But 
from several experiments it would appear 
that they are materially different in the laws 
of their production from those taking place 
in the first order. 
Thus, when single metallic wires with wa- 
ter are placed as series in powerful batteries 
of the second order, the influence producing 
oxygen seems to be transmitted by the point 
in the place of that part of the plate which 
was apparently incapable of undergoing oxi- 
dation ; whilst the hydrogen is evolved from 
that point where the oxidating part of the 
primary series appeared to exist. 
The agency of the galvanic influence, 
which occasions chemical changes and com- 
municates electrical charges, is probably in 
some measure distinct from that agency 
which produces sparks and the combustion of 
bodies. 
The one appears (all other circumstances 
being similar) to have little relation to sur- 
face in compound circles, but to be great in 
some unknown proportion, as the number of 
series are numerous. The intensity of the 
other seems to be as much connected with 
the extension of the surfaces of the series as 
with their number. 
Thus, though eight series composed of 
plates of zinc and copper, about 10 inches 
square, and of cloths of the same size, moist- 
ened in diluted muriatic acid, give sparks so 
vivid as to burn iron wire, yet the shocks 
they produce are hardly sensible, and the 
chemical changes indistinct ; whilst 24 series 
of similar plates and cloths, about two inches 
square, which occasion shacks and chemical 
agencies more than three times as intense,, 
produce no light whatever. 
A measure of the intensity of the power 
hi galvanic batteries, producing chemical 
changes,, may be derived from the quantity 
GAL 
of gas it is capable of evolving from water in 
a given time. 
The preceding facts can hardly leave any 
doubt with respect to the identity of the gal- 
vanic power and the electricity which is pro- 
duced by means of a common electrical ma- 
chine, or that is brought down from the 
clouds ; but, what is still more remarkable, 
it reconciles to the same principle the animal 
electricity, viz. the power of the torpedo, 
gymnotus electricus, &c. since all the phe- 
nomena of the animal electricity agree with 
those of the galvanic battery. See Elec- 
tricity. 
But the most striking circumstance is, that 
the electric organ of any of the above-men- 
tioned fishes seems to be constructed exactly 
like a galvanic battery; for it consists of 
little laminae or pellicles arranged in columns, 
and separated by moisture. It seems, in 
short, to be a galvanic battery, consisting of 
conductors of the second order only, but un- 
doubtedly of different conducting powers. 
Though the galvanic battery exhibits all 
the leading properties of common electri- 
city, such as the attraction, the spark, &c. 
yet in some effects, viz. the decomposition 
of water, oxygenation of metals, &c. the for- 
mer seem to differ considerably from the lat- 
ter; but those apparent differences have 
been sufficiently reconciled by some very 
ingenious experiments and observations of 
Dr. YV. li. Wollaston. See Phil. Trans. 
1801. 
With respect to the decomposition of wa- 
ter, which was thought to require very pow- 
erful electrical machines, he justly suspected, 
that by reducing the surface of communica- 
tion, the decomposition of water might be 
effected with less powerful means ; and this 
was verified by actual experiments. “ Hav- 
ing,” he says, “ procured a small wire of fine 
gold, and given it as fine a point as I could, 
I inserted it into a capillary glass tube ; and 
after heating the tube so as to make it ad- 
here to the point, and cover it in every 
part, l gradually ground it down, till, with 
a pocket-lens, 1 could discern that the point 
of the gold was exposed. 
“The success of this metlvod exceeding 
my expectations, I coated several wires in 
the same manner,, and found that when 
sparks from the conductors were made to 
pass through, water by means of a point so 
guarded, a spark passing to the distance of 
one-eighth of an inch would decompose wa- 
ter, when the point exposed did not exceed 
_l~ of an inch in diameter. With another 
7 O Q 
point which I estimated at of an inch, 
a succession of sparks, . J- of an inch in length, 
afforded a current of small bubbles of air. 
“ I have since found that the same appara- 
tus will decompose water with a wire of 
an inch diameter, coated in the manner be- 
fore described, if the spark from the prime 
conductor passes to the distance of of an 
inch of air: 
lie also found that with a gold point simi- 
lar to, but much smaller than any of the 
above-mentioned, and similarly situated in 
water, the mere current of electricity, with- 
out any sparks, would occasion a stream of 
very small bubbles to rise from the extremity 
of the gold. 
“ Having coloured a card,” he adds, “ with 
a strong infusion of litmus, 1 passed a current 
307 
of electric sparks alomr it, by means of two 
fine gold points, touching it at the distance 
of an inch from each other. The effect, as 
in other cases, depending on the smallness of 
the quantity of water, was most discernible 
when the card was nearly dry. In this state, 
a very few turns of the machine were suffi- 
cient to occasion a redness at the positive 
wire, very manifest to the naked eye. The 
negative wire being afterwards placed on the 
same spot, soon restored it to its original blue 
colour.” 
Dr. Wollaston likewise remarks another 
strong point of analogy between the electri- 
city of the galvanic battery and that of a, 
common electrical machine, viz. that they 
both seem to depend upon oxidation. In, 
fact, a common electrical machine will act 
more or less powerfully, according as the 
amalgam which is applied to its rubber con- 
sists of metals that are more or less oxidable- 
GAMBEZON, or Gamba, in antiquity, 
a kind of soft quilted waistcoat, worn under 
the coat of mail to prevent its hurting the 
body. It was made of wool or cotton, quilt- 
ed between two stuffs, and was also called, 
counterpoint. 
GAMBOGE, is a. concreted vegetable 
juice, and is partly of a gummy and partly 
of a resinous nature. It is brought to us 
either in form of orbicular masses, or of cy- 
lindrical rolls of various sizes, and is of a 
dense, compact, and firm texture, and of a 
beautiful yellow. It is chiefly brought tons 
from Cambaja, in the East Indies, called also- 
Cambodja and Cambogia ; and thence it has- 
obtained its names of cambadium,. cambo- 
gium, and gambogium. 
It is a very rough and strong purge ; it 
operates both by vomit and stool, and both 
ways with much violence, almost in the in- 
stant in which it is swallowed, but yet with- 
out griping. It requires caution and judg- 
ment in administering it; but those who know 
how to. give it properly, find it an excellent 
remedy in dropsies, cachexies, jaundice, asth- 
mas, catarrhs, and iix the worst cutaneous- 
eruptions. 
Its dose is from two or three grains to six, 
eight, or ten: four grains generally operate- 
briskly without vomiting, and eight or tea 
grains usually vomit briskly, and afterwards 
purge downwards. 
It is at present much more esteemed by 
painters in water-colours than by physicians. 
GAME, in general, signifies any diversion 
or sport that is performed with, regularity,, 
and restrained to certain rules. 
Games are usually distinguished into those 
of address and those of hazard. To the first 
belong chess, tennis, billiards, wrestling, &e„ 
and to the latter those performed with cards 
or dice, as back-gammon,, ombre, picquet, 
whist, &c. 
It would be a most salutary maxim to be-- 
adopted generally, that no game should be- 
pursued but such as afforded exercise, and 
consequently contributed toff he health of the- 
body. In this view we greatly prefer such as 
tennis and billiards- to the pernicious sedemj 
tary games at present pursued, which are- 
only productive of gouts, palsies,. & c. 
Games, in antiquity, were public diver-- 
sions, exhibited on solemn occasions. Such*. 
