Compound Galvanic Circles. 15 
and allow a free action of the liquid upon them at every immer- 
sion. 
. From the preceding experiments, we have seen that when the 
electricity is made to pass through the liquid for a considerable 
distance, in the case of a simple galvanic circle, it is no longer ca- 
pable of affecting the needle or heating the wire. It has been fully 
ascertained that electricity of a low intensity affects the needle, 
and raises the temperature of iron wire, while that of a high inten- 
sity acts more powerfully in chemical decomposition. 
- The subject of inquiry then is, What is the nature of this change 
that takes place in the electricity ? Does the quantity of electricity 
circulating along the wire remain the same, having only its inten=- 
sity increased by passing through a greater extent of liquid, and 
thereby becoming incapable of affecting the needle or heating the 
Wire ? or is it absorbed by the liquid in its passage through it ? or, 
according to Dr Hare’s theory, does the electricity alone pass 
through the liquid, while the caloric is absorbed by it ? 
The chemical action upon the plates continued the same at what- 
ever distance they were removed from each other ; hence the gene- 
ration of electricity ought to have been the same at all distances. 
From these experiments, I had some reason to think that the elec- 
tricity is not absorbed in its passage through the liquid, but mere- 
ly increased in its intensity ; and consequently, that by increasing 
the distance between the plates, a change of the electricity would 
take place, from that of a low to a medium intensity, or that state 
of electricity which is capable of decomposing liquids ; and that, 
by increasing the distance of the plates still farther, nearly the 
pure electrical effects, or those of De Luc’s column weuld be pro- 
duced ; so that from the simple galvanic circle, electricity of any 
intensity might be procured, provided the distance between the 
plates was of sufficient extent. From the difficulty of obtaining a 
trough large enough to immerse the plates in, in order to discover 
whether I was correct or not in this opinion, I had recourse to the 
expedient of immersing them in the sea. 
~ The experiments were performed on the Chain Pier, Newhaven, 
which projects into the sea nearly 600 feet, on Wednesday the 5th 
August 1829, in presence of Captain Thomas Brown, and Messrs. 
Cheek and Ainsworth. 
' A plate of copper and one of zine were prepared, 12 inches square. 
A copper wire was then soldered to each of them, 200 feet in 
length. Fine platina wires were also soldered to the extremities 
of each of the copper wires. ‘The plates being thus prepared, two 
of the gentlemen who assisted me, stood on the pier, at a distance 
of nearly 300 feet from each other, one of them having the copper 
and the other the zinc plate, who were ready, at a given signal, to 
immerse them into the sea by the wires that were attached to them. 
The wires were continued along the pier, so as to meet in the 
middle to complete the circuit, at equal distances from the plates, 
where the experiments were performed. . 
