Crosse’s. Experiments with the Voltaic Battery. 133 
batteries at work. One consisting of eleven pairs of cylinders, 
made of four inch plates, between the poles of which is placed a 
glass cylinder, filled with silicate of potassa, in which is suspended 
a piece of slate between two wires of platina, as before, and cov- 
ered loosely with paper. Here, again, is another crop of insects 
formed. The other battery consists of twenty pairs of cylinders, 
the electric current of which is passed through six different solu- 
tions in glass cylinders, in three of which only is the insect form- 
ed, viz. Ist, in nitrate of copper; 2d, in sulphate of copper, in 
each of which the insect is only peodatied at the edge of the fluid, 
as far as I can make out; and 3d, by the old apparatus of coiled 
silver and iron wire in sllielte of potassa, as before. There are 
now forming on the bottom of this positively electrified wire sim- 
ilar insects, at the distance of fully two inches below the surface 
of the fluid. On examining these, I have lately noticed a peculiar 
quality they possess whilst in an incipient state. After being kept 
some minutes out of the solution, they contract their filaments, so 
as, in some cases, wholly, and in others partially, to diiappou 
Tat first thought they were destroyed; but, on examining the 
same spots, on the next day, they were as perceptible as before. 
In this respect, they seem not unlike the zoophytes, which adhere 
to the rocks on the sea-shore, and which contract on the approach 
- of a finger. I may likewise remark, ‘that I-have not been able 
to detect ‘their eyes, even when viewed under a powerful micro- 
scope, although I once fancied I perceived them. The extreme 
heat of summer and cold of winter do not appear favorable to their 
production, which succeeds best, I think, in spring and autumn. 
As in the above account I have occasionally made use of the word 
“ formation,” I beg that it might be understood that I do not mean 
creation, or any thing approaching to it. [am not aware that I 
have any thing more to add, except the few —_— I shall con= 
clude with. - 
1st. I have not observed-a formation. of the insect, except on a 
moist and electrified surface, or under an electrified fluid. By 
this J do not mean to assert that electricity has any thing to do 
with their birth, as I have not made a sufficient number of exper- 
iments to prove or disprove it; and besides, I have not taken 
those necessary precautions which present themselves even to an 
unscientific view. These precautions are not so easy to observe 
as may at first sight appear. It is, however, my intention to repeat 
