Mr. Crosse's Electrical Experiments. 103 



first each of them fixed itself for a considerable time in one 

 spot, appearing 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. On being examined with a micro- 

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

 larger ones eight. Mr. Crosse states that " It would be su- 

 perfluous to attempt a description of these insects, when so 

 able a one has been transmitted from Paris. It seems they 

 are of the genus Acarus, but of a species not hitherto obser- 

 ved." They have been seen and examined by many scientific 

 men and eminent physiologists, who all coincide with the o- 

 pinion of M. Turpin, and the members of the Academie des 

 Sciences, as to their genus and species. Mr. Crosse has ne- 

 ver ventured an opinion as to the cause of their birth. He 

 conjectured that they arose from ova, deposited by insects 

 floating in the air, and that they might possibly be hatched 

 by the electric action ; but he could not imagine that an ovum 

 could shoot out filaments, and that these filaments would be- 

 come bristles ; and he could not, on the closest inspection, 

 detect any remains of a shell. Moreover, we have no right to 

 assume that electric action is necessary to vitality, until such 

 fact shall have been most distinctly proved. Mr. Crosse next 

 imagined their origin to be from the water, and closely exa- 

 mined several hundred vessels in the- same room, filled with 

 the same water as that which held in solution the silicate of 

 potassa, but could perceive no trace of an insect of that de- 

 scription. He then examined the crevices and dusty parts 

 of the room, with no better success. In the course of some 

 months these insects so increased, that when they were strong- 

 enough to leave their moistened birthplace, they issued out in 

 different directions, Mr. Crosse supposed in quest of food, but 

 they generally huddled together under a card, or piece of pa- 

 per, in their neighbourhood, as if to avoid light and disturb- 

 ance. In the course of experiments on other matters, a glass 

 basin was filled with a concentrated solution of silicate of po- 

 tassa, without acid, in the middle of which was placed a piece 

 of brick, consisting chiefly of silica, connected at each end 

 with the poles of a voltaic battery, of sixty-three pairs of 

 plates, each about two inches square. After many months' 

 action, silica, in a gelatinous state, formed on the bottom of 

 the brick, and as the solution evaporated, it was replaced by 

 additions, so that the outside of the glass basin, being con- 

 stantly wet by repeated overflowings, was of course constant- 

 ly electrified. On this outside, as well as on the edge of the 

 Vol. II.— No. 14. n. s. i 



