powder while still warm, nie b 
‘ 
Crosse’s Experiments with the Voltaic Battery. 127 
quart: basin on a circular piece. of mahogany placed within the 
faivtell When this basin was filled with a fluid, a strip of flannel 
wetted with the same, was suspended over the edge of the basin 
and inside the funnel which, acting as a syphon, conveyed the 
fluid out of the. basin, through the-funnel, in successive drops. 
The middle shelf of the frame was ihewies pierced with an aper- 
ture, in which was fixed a smaller funnel of glass, which sup- 
ported a piece of somewhat porous red oxide of iron from: Vesuvi- 
_ us, immediately under the dropping of the upper funnel. ‘The 
stone was kept constantly electrified by means of two. platina 
wires 6n either side of it, connected with the poles of a Voltaic - 
battery of nineteen pairs of five-inch zinc and copper single plates, 
in two porcelain troughs, the cells of which were filled at first 
with water and =}, of hydrochloric acid, but afterwards with wa- 
ter alone. _ I may here state, that in all my subsequent experi- 
ments relative to these insects, I filled the cells of the batteries 
employed with nothing but common water. 'The lower shelf” 
merely supported a wide-mouthed bottle, to receive the drops as 
they fell from the second funnel. When the basin was nearly 
emptied, the fluid was poured back again from the bottle below 
into the basin above, without disturbing the position of the stone. 
It was by mere chance that I selected this volcanic substance, 
choosing it from its partial porosity; nor do I believe. that it had 
the slightest effect in the production of the insects to be described. 
The fluid with which I filled the basin was made as follows. 
‘I reduced a piece of black flint to powder, having first exposed 
_ it to a red heat and quenched it in water to make it friable. Of 
this powder I took two ounces, and mixed them intensely with 
six ounces of carbonate of potassa, exposed them to a strong heat 
for fifteen minutes in a black lead ¢ epewie a an air furnace, and 
on an iron plate, reduced it to 
oiling water ‘on it, and kept it 
boiling for some minutes ina sand bath. 'The greater part of the 
soluble glass thus fused, was taken up by the water, together 
with a portion of alumina from the crucible. . I should have used 
one of silver, but had none sufficiently large. To a portion of 
- the silicate of potassa thus fused, I added some boiling water to 
dilute it, and then slowly added hydrochloric e acid to supersatu- 
ration. “A strange remark-was made on this part of the experi- 
Ze at the meeting of the British Association at Liverpool, it 
