a 
128 Crosse’s Experiments with the Voltaic Battery. 
being then gravely stated, that it was impossible to add an acid 
‘to a silicate of potassa without precipitating the silica! This, of 
course, must be the case, unless the solution be diluted with wa- 
ter. My object in subjecting this fluid to a long-continued elec- 
tric action, through the intervention of a porous stone; ‘was to 
form, if possible, crystals of silica at one of the poles of the bat- 
“tery, but I failed in accomplishing this by those means. On the 
fourteenth* day from the commencement of the experiment, I 
observed, through a lens, a few small whitish excrescences or 
nipples projecting from about the middle of the electrified stone, 
and nearly under the’ dropping: of the fluid above. On. the 
_eighteenth* day, these projections enlarged, and seven or eight 
filaments, each of them longer than the-excrescence from which 
it grew, made their appearance on each of the nipples. On the 
‘twenty second* day, these appearances. were more elevated and 
distinct, and on the twenty sixth* day, each figure assumed the 
‘form of a perfect insect, standing erect on a féw bristles which 
formed its tail. ‘Till this period I had no notion that these ap- 
pearances were any other than an incipient mineral formation; 
but it was not until the twenty eighth day, when I plainly per- 
ceived these little creatures move their legs, that I felt anysur- 
prise, and I must own that when this took place, I was not a little 
astonished. - 1 endeavored to detach, with the point of a needle, 
one or two of themfrom its position on.the stone, but they im- 
mediately died, and I was obliged to wait patiently for a few days 
_ longer, when*they separated themselves from the stone, and 
moved about at pleasure, although they had been for some time 
after their birth apparently averse to motion. In the course of a 
few weeks, about a hundred of them made their appearanee on 
the stone. I observed that at first each of them fixed itself for 
a considerable time in one spot, appearing, as far as I could judge, 
to feed by suction ; but when a ray of light from the sun was 
directed upon it, it seemed disturbed, and removed itself to the 
shaded part of the stone. Out of about a’ hundred insects, not 
"above five or six were born on the south side of the stone. “1 
examined some * ooncpeg the microscope, and‘ observed that 
t have only six legs, but. the larger 
rfl jpastdrnpt a ae of 
e 22, and 26 Paar pe ~ ae 
