88 
History. galts, they found that there was a transfer of the acid 
~—y~=" and alkali to different parts of the ps Pater They 
formed the general conclusion, that whenever electri- 
city is sent across a fluid, it disposes its constituents to 
separate and pass to the two sides respectively ; com- 
bustible substances, alkalies, and are attracted 
to the negative; acids, oxides, &c. to the positive ex- 
tremity of the pile. The force of the decomposition 
they suppose is in the ratio of the quantity of electri- 
city, and that the electricity is in proportion to the sur- 
face of metal which is in contact with a moist conduc- 
tor. The decomposition is also influenced by the affi- 
nity of the components of the substance, its power of 
conducting electricity, and other circumstances. See 
Ann. de Chim, li. 167. : f , 
. Mr Cruickshanks, among his earliest discoveries, had 
observed, that an acid and an alkali were generated at 
the two ends of the wires in the interrupted circuit, and 
this fact’ had been confirmed by other (oe PT 
The substances produced were supposed to be nitric 
acid and ammonia; the first originating from the union 
of oxygen with the azote of air dissolved in the water, 
the latter from hydrogen combining with the same ele- 
ment. But it was now announced that muriatic acid 
‘and soda were generated by passing the electric current 
through pure water, and where this salt could not be 
suspected to be present in any part of the apparatus, or 
Supposed 
production 
of muriatic 
acid. 1805. 
in any of the materials employed. In the spring of 1805, ” 
the following letter was published, purporting to be writ- 
ten by Mr Peel of Cambridge: ** I took about a pint of 
distilled water, and decomposed about one half of it by 
means of galvanism, the other half I evaporated, and 
found to remain at the bottom of the glass a small quan- 
tity of salt, which, upon examination, proved to be muri- 
ate of soda, The salt could not have been contained in 
the water before I made the experiment, because I used 
every precaution to have it free impurities. Ieven 
took the trouble to repeat the experiment, though a tedi- 
ous one, and I again obtained the same result. A friend 
.of mine has just informed me that he has tried my ex- 
‘periment, and has succeeded in procuring the salt.” See 
‘Tilloch’s Mag. xxi. 279. 
Peel’s ex- 
periments. 
Pacchioni’s Almost at the same time that this notice was publish- 
experi- ed in London, Pacchioni, professor at Pisa, gave an 
ments, 
account of some experiments the action of gal- 
vanism on water, in which he obtained results analo- 
gous to those stated above. He informs us, that when 
water had been for a long time subjected to the galva- 
nic influence, and had been ing with its oxygen 
from the extremity of a gold wire, the fluid was found 
to.contain a quantity of oxymuriatic acid. From this 
experiment he drew the following conclusions: Oxy- 
muriatic acid is an oxide of hydrogen; it consists of 
water deprived of part of its oxygen ; muriatic acid is 
water in a still “0 degree of oxidation ; and, of 
course, oxygen and hydrogen are susceptible of diffe- 
— megane of oxidation. See Edinburgh Med. Journ. 
1 3 
A great degree of attention was excited by. these ex~ 
periments, to which the more credit was attached, be- 
eause they from sources entirely independent 
of each other. They were repeated by different expe- 
rimentalists in this country, and in some cases with ap- 
parent success. Mr Sylvester in particular, obtained 
traces both of muriatic acid and soda, where proper pre- 
cautions were supposed to have been taken, to ex- 
elude the muriate of soda from every part of the appa- 
natus. But from facts. which have been 
discovered, we may conclude, that the substances ob« 
Not con- 
firmed. 
GALVANISM. 
tained in these cases were not derived from the decom- 
position of the water. Paechioni’s experiments are now 
universally admitted to have been incorrect ; and it ap- 
pears that no such individual as Mr Peel could be found 
in Cambridge, so that the letter bearing his name is a 
complete fabrication. It was not, however, entirely 
without its use ; for the minute examination of the ef- 
fects of galvanic electricity upon water, to which it gave 
rise, may probably be regarded, in some measure, as 
the immediate cause of Sir H. Davy’s most important 
discoveries. heh ee 
An elaborate memoir was, about this time, written by frman’ 
Erman, on the conducting power. of different bodies, experi. 
which obtained the prize from the French Institute, ments. 
His object was to remove some anomalies, which ap- 15° 
peared to exist in the relation of the galvanic electricity od 
to the different conducting s' ie 
He divides all bodies into five classes: Ist, Perfect Five sp 
non-conductors ; 2d, Perfect conductors; 3d, Im cies of | 
conductors; 4th, Positive conduetors ; and 5th, Nega- dies, 
tive conductors. The nature of the three first classes 
requires no explanation ; the fourth and fifth class of 
bodies act as perfect conductors, when applied to either 
of the two separately, but when placed be- 
tween them, insulate either the positive or negative pole 
respectively, and do not form a communication between 
them. The flame of a spirit lamp is described as a por Plame a 
sitive conductor ; if it be applied to as separates sitive 
ly, it conducts the electricity ; but if it be placed be- ductor, 
tween the two poles, it will not form a communication 
between them, in consequence of its insulating the ne- 
gative electricity. A flame is pera, Ph of 
anism, it does not conduet it so as metals. 
o effect is produced, when flame is between 
the extremities of the pile. 
Flame is, however, a very 
different substance aceording to the body from w 
it is red: the above observation refers to the flame 
of a Spdcssepsbubets body. The flame of sulphur in- 
sulates both the poles; and that of phosphorus insulates 
the positive, and conducts the negative influence, ‘Phos« 
— must therefore be placed in the fifth class*of bo- 
‘dies; and perfectly dry soap is also a negative conduc- 
eae 
The author gives an account of a number of experi- be 
ments that he rd on this latter substance, 
of which are eurious and original. Hard soap, when ¢ 
perfectly dry, if ied to either end of the galvanic 
pile, conducts all the electricity from that extremity in- 
to the ground, and there appears to be no perceptible 
difference in its action upon the two extremities. If 
wires be connected with each end, and be made to ter+ 
minate in a prism of hard dry soap, which is insu- 
lated, the circuit will not be eted ; but if this soap ‘ 
beuninsulated, by establishing a communication withthe ~ 
ground, an electrometer conneeted with the positive _ 
pole, manifests a great degree of divergence, while one 
on the negative pole loses all signs of it. Con 
ly,” M. Erman observes, “ the soap which insulates the 
positive effect, is a perfect conductor for the negative.” 
As a proof and illustration of this property, the author: 
informs us, that * if one finger be ied to the wire 
of the positive pole, and another finger wetted to. the 
soap, no shock is felt, and the electrometers do not show 
the least change in their respective divergencies. But 
if the experi be repeated, by establishing a com- 
munication between the positive pole and the soap with 
both fingers wetted, a very perceptible shock will be 
felt, and the two electrometers will arrive at an. equal, 
and a very weak degree of intensity.” He proposes the 
