44.1 
ELECTRICITY. 
blooded animal, fimilar effects will enfue, A curious 
experiment was tried by La Grave, and related in the 
Memoirs of the Galvanic Society of Paris. A feries of 
g.d vanic combinations having been formed of brain and 
mufcle, cut into fliccs, and layers of hat, moiftened in 
folurjon-of the. muriat of foda, evident galvanic effects 
were induced. 
Animal fubftances are fuperior condudtors to thofe 
which belong to the vegetable kingdom. The fubftances 
which conftitute the intermediate link between animals 
and vegetables, Arch as nmftirooms and morells, preferve 
the fame order in their Gondufting powers. Gehlefi, in 
his Philofophical Dictionary, firft remarked this curious 
circumftance, which is not dependent on their humid 
date, (ince, when they are cut and dried, they are found 
to be good conductors. 
Vaiii was the firft to notice that a ligature applied to a 
nerve, prevents the mufcle from being convulfed by me¬ 
tals. Trattori obferved, that this is not an invariable 
confequence. Valli, in his fubfequent obfervations, dif- 
covered, that if the ligature be made elofe to the infer- 
tion of the nerve in the mufcle, it entirely impedes its 
movements ; but if at a diftance, the experiment i'ucceeds. 
perfectly well. However a nerve may be lacerated, if a 
final 1 fibre of communication be left, the convulfions will 
be produced. When the nerves of warm-blooded animals 
are applied to the nerves of cold-blooded animals, the 
contractions do not take place. Thus, the crural nerve of 
a moufe being applied to the crural nerve of a frog, and 
the nerves feparated by about the half of a line, the con¬ 
tractions do not enfue. But if a nerve of the fame frog 
be divided, and the parts feparated about a line from 
each other, upon completing the circuit, the contractions 
will take place. 
After pointing out thefe fimple galvanic combinations, 
it will be proper to advert to the effect of an increafe of 
the feries of metals. Volta obferves, that “ a feries of 
this nature refembies an eleCtric battery, weakly charged,^ 
aCting inceffantly, and which charges itfelf after each 
explolion.” Inftead of confiding of infulating plates or 
electric ftrata, it is armed with conductors. The firft ar¬ 
rangement he terms a couronne de tajfes, confiding of glafs 
tumblers, half filled with water, or fait and water, and 
forming a regular union by a feuies of metallic arcs, as 
reprefented at fig. 30, in which the plates marked S, are 
either of filver or copper, and thofe marked Z, of zinc. 
The arcs a, a, a , may be formed of any fubftance which 
is a good conductor of eleCtricity ; and the two metals in 
each glafs fhould be foldered to the metallic arc, in any 
part above the one which is immerfed in the liquid. Volta 
remarks, that alkaline folutions are employed with the 
bed: effeCt, when one of the metals is tin, and the other 
lilver or copper. If zinc be fubftituted for tin, then falt- 
water is preferable. When thirty or forty of thefe glades 
are arranged, one of the experimenter’s hands being 
placed in the fluid contained in the firft clafs, and.the 
other hand in the la ft of the feries, a fhock is experi¬ 
enced. As often as the circuit is completed, the fame 
fenfations recur. 
Mr. Cruickfhank, chemift at Woolwich, has confide- 
rably improved the conftruction of the Voltaic pile. Thus 
is reprefented in the EleCtricity Plate III. at fig. 31 ; 
where A B C D is a wooden trough formed of hard baked 
mahogany; about thirty inches long. Withinftde, fifty 
grooves are cut in the Tides and bottom, at equal diftances 
from each other. Thefe grooves fhould be of a thicknefs 
corref'ponding to the metallic plates in the Voltaic pile. 
The plates are cemented feparately in each of the grooves, 
fo that the fluid will not pals out of one cell into the 
other. The plates conlift of zinc foldered to copper; 
and in whatever direction- the firft: of them is cemented 
into the box, all the others mud preferve the fame order. 
Suppofing the copper fide of the firft to be towards B ; 
all the others fhould be fo placed in the box as to have 
their copper ficies towards B, and their zinc furfaces to¬ 
wards C. When they are thus arranged, the end C D is 
called the zinc end of the battery; and the end A B the 
copper end. In this date the inftrument is complete. 
This conftruCtion poffefies many advantages which the 
pile does not. The fluid is applied with greater facility. 
The apparatus is more Convenient for experiments; it 
continues to be aCtive confiderably longer; and is attended 
with little or no trouble ih cleaning. In the Voltaic pile, 
after it has been once 11 fed, the zinc furface of the plates 
becomes oxydated ; infomuch, that before they can again 
be ufed, they mud be (craped or filed, which is a tedious 
and troublefome operation. In the trough every fuccef- 
five operation cleans the plates, by diflolving the oxy¬ 
dated furface of the zinc. 
Volta fuppofed the fluid employed to a Cl merely as a 
conductor ; and that the differences in fluids depend en¬ 
tirely on their different conducting powers. It has been 
fliewn, by the experiments of Aftie, Creve, Fabroiii, and 
others, that the fluid aCts chemically 011 the eafieft oxyd- 
able metal ; and that thofe fluids produce the moft aCtive 
effects, which influence the metallic fubftance the moft 
powerfully. Thus acids, alkalies, neutral falls, &c. aCt 
more powerfully than fimple water. Acid folutions are 
fiill'more powerful than the former. One part of nitric 
acid, blended with about twenty parts of water, forms a 
very aCtive mixture. As this mixture evolves nitrous 
gas, ,it is injurious to refpiration ; befides which, the 
nitric acid is very expenfive. Sulphuric acid, combined 
with water, anfwers very well, but its aCtion is top quick. 
In operating on the zinc, it difengages fuch quantities of 
hydrogen gas, as to be very troublefome, and is frequent¬ 
ly attended with fuch evolutions of heat, as to loofen the 
cement. About an ounce of the muriatic acid, or fpirit 
of fait of the (hops, blended with a pint of water, con- 
ftitutes a convenient mixture, which u6ts tranquilly and 
uniformly, decompofmg the water fo (lowly, that the hy¬ 
drogen gas which is evolved does not annoy the opera¬ 
tor; the trough, by the employment of this acid mix¬ 
ture, is kept uniformly clean. 
When, for any experiment, feveral batteries are requi- 
fite inftead of one, they fhould be placed in precifely the 
fame order as if two, three, or more, batteries, were to con¬ 
ftitute one trough only ; obferving, throughout the whole 
of.the feries, that the zinc furface of one of the plates 
fhould be conflantly oppofite to the copper furface of the 
next plate in the feries ; and that the troughs fhould be 
connected to each other by fome metallic fubftance. A flip 
of copper ftieeting, about half the width of the trough, 
anfwers this purpofe very well. 
On the continent, the Voltaic pile dill continues to be 
employed; the advantages of Mr. Cruickfliank’s trough, 
perhaps, not being as yet known. To render its aCtion 
more permanent, Monf. Ifatn has fubftituted to the moif- 
tened cloths, fait juft fufficiently moiftened to be formed 
into a layer. He obferves, that a pile thus formed, re¬ 
tains its powers for a month. The quantity of metallic 
fubftance deftroyed by the acid is very trivial; fince it 
only aCts'when the circuit is completed. A trough, how¬ 
ever, will, with due care, laft ten or twelve years, if it 
even be employed feveral hours daily. The fluid, when 
poured in, fhould not afeend higher than about a fourth 
of an inch from the top of the plates ; and when the 
trough is filled, it fhould, as well as the upper furface of 
the plates, be wiped dry. 
When a fingle metal is employed, fuch as copper, the 
plates are cemented in the fame manner: in one of the 
cells fimple water is introduced ; and in the oilier a folu- 
tioti of nitric acid. This battery is by no means fo power¬ 
ful as when zinc is employed with copper, and one fluid 
only. So, likewife, if plates of gold and filver be foldered 
together, a folnlion of nitric acid will be found to anfwer, 
becaufe it will oxydate the filver, and not the gold. Any 
metallic combinations inay be formed, if the fluid which 
is employed will act on one of the metals, and not on the 
other: their powers will, however, be feeble, becaufe 
their 
