128 Crosse's Expei^iments 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 few 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 any sur- 

 prise, and I must own that when this took place, I was not a little 

 astonished, I endeavored to detach, with the point of a needle, 

 one or two of them from 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 appearance 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. I 

 examined some of them with the microscope, and observed that 

 the smaller ones appeared to have only six legs, but the larger 

 ones eight. It would be superfluous to attempt a description of 



* Denoted by the figs. 14, 18, 22, and 26. 



