ry: tensively employed in medicine, ially in those dis- 
Y——" eases where common electricity been previous] 
ved in (Und useful. It might have been expected that muc 
benefit would have been derived from so powerful an 
t, and one which is so easy of application to any 
of the body. Our expectations of advantage have, 
, aoc been generally disappointed. Flattering ac- 
counts of success were ind ublished, in different 
nervous disorders, in paralytic affections, in deafness, in 
some kinds of blindness, in the recovery of persons ap- 
tly drowned or suffocated, and even in hydropho- 
Bin ond | insanity. But we believe that the practice is 
now very generally relinquished, from a conviction of its 
inutility. 
Ritter published an account of a curious appendage 
to Volta’s pile, which he called the secondary pile, and 
which She eat frequently called the pile of Ritter. It 
is a kind of electric apparatus, which may be ge 
by the voltaic pile, or may be made to retain the elec- 
tricity that is ually flying off from this instru- 
ment. He perceived that a body, which had formed 
‘part of the galvanic circle in the pile of Volta, when 
the pile was removed, became itself electrical ; but it 
exhibited an electricity ephasie. to that which it had 
peri iously possessed. Thus, if two wires terminating 
water, and connected with the pile, were discharging 
one oxygen and the other hydrogen, when they were 
Hesciod foen it, they would still continue to discharge 
the gases, but the operation would be reversed. These 
wires, in this state, may be considered as charged, and 
greater number of similar wires be placed between 
‘the ends of the pile, they will all become charged. The 
nature of the experiment will not be affected, if, instead 
of wires terminating in water, plates of metal be sub- 
stituted, with wet cards interposed. An instrument 
will thus be formed, which of itself cannot produce any 
signs of electricity, but which may be rendered electri- 
cal, by being placed in contact with the primary pile. 
When the two piles are connected, the action of the 
ends of each are reversed to each other, and, as when 
they are separated, the ends of the secondary pile are 
again reversed, consequently the ends of both the piles 
will now act in the same manner, It is necessary for 
_ the pile of Ritter to remain for some time in contact 
with the pile of Volta, in order that it may be sufficient- 
ly charged. It is stated that the chemical effect of 
Ritter’s pile, that is, its effect in decomposing water, 
does not bear a regular ratio to its physiological effect, 
that is, its effect in giving shocks. The author observes, 
‘with respect to the voltaic pile, that its tension is the 
greatest, and it produces the strongest effects on the 
sensations immediately after it is constructed, but that its 
chemical effects are the most powerful after it has been 
acting for some hours. See Journ. de Phys. lvii. 345. 
r ex-- Shortly after the publication of the account of the se- 
iments con pile, Ritter made a number of experiments with 
\fe ad the pile of Volta, which are original curious. He 
te. vol- observed that when a communication was formed be- 
tween the positive end of the voltaic pile and the earth, 
the whole instrument became negatively electrified, and 
when the communication was made with the negative 
end, the instrument became itive. These changes 
do not, however, destroy the eioal action of the pile, 
which, goes on in the same manner as before the com- 
munication was formed, He supposes that the decom- 
position of water is effected in consequence of the po- 
sitive end disengaging oxygen, and the negative end 
hydrogen, and that the two ends haye also a tendency 
. 
7 
ma 
= 
Eo 
GALVANISM. 
87 
and hydrogen History. 
psy ypaect gS He says, if the positive end be armed ““y"” 
with gold leaf, and the negative with charcoal, and 
these substances be then brought into contact, the gold 
will be burned ; but if the ition of the substances 
be reversed, the charcoal will be burned. When the 
extremities of a pile do not communicate, it is said that 
the action exercised between the different plates is v 
unequal; the zinc, which is nearest the positive end, A 
is the most oxidated. It is also asserted, tifa pile Different 
be broken into separate parts, by a number of wires S500)" 
inserted between every fifth pair of plates, those wires parts of the 
nearest the positive end will be the most oxidated ; pile. 
while, on the contrary, those wires near the negative 
end will be less oxidated than if they had been sim- 
ply plunged in water. Hence he infers, that at the 
negative end an action has taken place, or a state has 
been induced, the reverse of oxidation. He goes so far 
as to say, that different sensations are excited by the 
two ends of the pile, the one expanding, and the other 
contracting, the muscular fibre; the positive end 
strengthens the pulse, and produces heat, the nega- 
tive weakens it, and produces cold. See Journ. de 
Phys. lvii. 401. 
far as we have been able to learn, few, if any, of Remarks 
the experiments of Ritter have been repeated, either in on Ritter’s 
is pe or in. France ; a circumstance which is not a ¢xperi- 
little remarkable, when we consider that many of them ™¢** 
are quite original, and would lead to important theore- 
tical deductions. His lan and manner of writin 
are, however, unfortunately obscure ; and he abounds 
so much in hypothesis, that he has not obtained that 
degree of attention to which he would seem to be en- 
titled, from his industry and ingenuity. It is scarcely 
to be supposed that he could have been mistaken re~ 
specting the effect of the secondary pile, or that he 
would face invented a series of facts, the fallacy of 
which might be so easily detected. With respect to 
the experiments on the voltaic pile, their authority is 
more doubtful; they seem to have been performed with 
a manifest view to a particular hypothesis ; some of 
them are of an indeterminate nature, and we may ima- 
gine that many are exaggerated, or even inaccurately 
stated. 
The attention of the different experimentalists was Biot's opi- 
now much occupied with the comparative merits of the nions re- 
two hypotheses, the electrical and chemical ; generally ‘Pecting the 
pays the English seemed to incline to the latter; and meas 
e continental writersto the former. Biot drew up a can nic action, 
did and judicious memoir, in which he compares the 
merits of the two opinions, and endeavours to shew 
how far either of them is supported by acknowledged 
facts. Electricity, he observes, is certainly excited, but 
it is not certain whether we ought to regard it as cause 
or effect. He proceeds to inquire, whether the action 
of the instrument depends entirely upon the oxidation 
of the water, entirely upon the influence of the metals, 
or whether it is not produced by the two in conjunc 
tion. This he decides to be the case ; and yet, at the 
same time that he makes this. decision, he appears to 
have a leaning towards the chemical hypothesis. See 
Ann. de Chim, xlvii. 1. 
In the year 1804, a very valuable memoir was writ- Hisinger 
ten by Hisinger and Berzelius, which must be regard- and Ber- 
ed as containing the fundamental principle of those 2elius on 
doctrines, which have since been so extensively deve- sy pr por 
loped by Sir Humphry Davy. the galva- ., a) 
stances, 
By passin 
nic influence through solutions of the different neutral 1994, 
to dispose metals to unite with oxy 
