TT ee i 
Crosse’s Experiments with the Voltaic Battery. 131 
Sulphate of zinc: 6. Water acidified with a minute portion of 
hydrochloric acid: 7. Water poured on powdered metallic arse- 
nic, resting on a copper cup, connected with the positive pole of 
the battery. All these cylinders were electrically united to- 
pethes by "ares of sheet copper, so that the same electric current 
through the whole of them. 
‘many months’ action, and consequent formation of certain 
exghtaltina matters, which it is not my object here to notice, I ob- 
served similar excrescences with those before described at the 
edge of the fluid in every one of the cylinders, excepting the 
two which contained the carbonate of potassa, and the metallic 
arsenic ; and in due time a host of insects made their appearance 
It was curious to observe the crystallized nitrate and. sulphate of 
copper, which formed by slow evaporation at the edge of the re- 
spective solutions, dotted here and there with these hairy excres- 
cences. At the foot of each of the cylinders, I had placed a paper 
ticket upon the table, and on lifting them up, I found a little 
colony of inseets under each, but no appearance whatever of their 
having been born under their respective papers, or on any part of 
the table. The third battery consisted of twenty pairs of cylin- 
ders, each equal to a three inch plate. Between the poles of this 
I interposed likewise a series of six glass cylinders, filled with 
various solutions, in only one of which I obtained the insect. 
This contained a concentrated solution of silicate of potassa. 
A bent iron wire} one fifth of an inch in diameter, in the form of 
an inverted syphon, was plunged some inches into this solution, 
and connected it with the positive pole, whilst a small coil of fine 
silver wire joined it with the negative. © 
After some months’ electrical action, gulstindagjeitiba enraged 
both wires, but in much greater quantity at the positive pole; “aud 
in about eight months from the 
on exainining these two wires very minutely, by means ofa lens, 
having removed them from the’solution for that purpose, I plainly 
perceived one of these incipient insects upon the gelatinous silica 
on the silver wire, and about half an inch below the surface of the 
fluid, when replaced in its original position. In the course of time, 
more insects made their appearance, till, at last, I counted at once 
three on the negative and twelve on the positive 
them were formed on the naked -of the wires, that is, on that 
part which was partially bare of gelatitifns silica: but they. were 
