164 MISCELLANEOUS COMMUNICATIONS. 



filled at first with water, and 1 -500th of hydrochloric acid, but afterwards 

 with water alone. (In all the subsequent experiments relative to these in- 

 sects the cells of the batteries employed were filled with nothing but com- 

 mon water.) The lower shelf merely supported a wide-mouthed bottle, to 

 receive the drops as they fell from the second funnel, to be poured back 

 again into the basin above, without disturbing the position of the stone. The 

 volcanic substance was selected by mere chance, in consequence of its partial 

 porosity, and Mr. Crosse did not believe it had the slightest effect in the 

 production of the insects. The fluid with which the bason was filled was 

 made as follows: — A piece of black flint having been exposed to a red heat, 

 and quenched in water, to make it friable, was reduced to powder, two ounces 

 of which were intimately mixed with six ounces of carbonate of potassa, and 

 the compound was exposed to a strong heat for fifteen minutes in a black 

 lead crucible, in an air furnace. In this fused state it was poured on an iron 

 plate, reduced to powder, whilst still warm, and boiling water poured upon 

 it ; it was, then kept boiling for some minutes in a sand bath. The greater 

 part of the soluble glass thus formed was taken up by the water, together 

 with a portion of alumina from the crucible (a silver one would have been 

 used, but Mr. Crosse had none sufficiently large). To a portion of the sili- 

 cate of potassa thus formed boiling water was added, to dilute it, and then 

 slowly to supersaturation, hydrochloric acid. This fluid was subjected to a 

 long-continued electric action, through the intervention of a porous stone, in 

 order that, if possible, crystals of silica might be formed at one of the poles 

 of the battery ; but Mr. Crosse failed in accomplishing this by these means. 

 On the fourteenth morning from the commencement of the experiment, were 

 observed, through a lens, a few small whitish excrescences or nipples, pro- 

 jecting from about the middle of the electrified stone, and nearly under the 

 dropping of the fluid above. On the 18th day these projections were en- 

 larged, and seven or eight filaments, each of them larger than the excres- 

 cence from which it grew, made their appearance on each of the nipples. 

 On the 22d day these appearances were more elevated and distinct ; and on 

 the 26th day each figure assumed the form of a perfect insect, standing erect 

 on a few bristles which formed its tail. Until this period, Mr. Crosse had 

 had no notion that these appearances were any other than an incipient 

 mineral formation ; but it was not until the 28th day, when he plainly per- 

 ceived the little creatures move their legs, that he felt any surprise ; and 

 when this occurred, as may be easily imagined, he was not a little astonished. 

 Mr. Cross endeavoured to detach, with the point of a needle, one or two of 

 them from their position on the stone ; but they immediately died, and he 

 was obliged to wait patiently a few days longer, when they separated them- 

 selves 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. 

 At first, each of them fixed itself, for a considerable time, in one spot, ap- 

 pearing 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 microscope, 

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

 Mr. Crosse states that " it would be superfluous to attempt a description 



