Crosse's Experiments with the Voltaic Battery. 135 



however the timid may shrink from investigation, the more com- 

 pletely the secrets of natm'e are laid bare, the more effectually 

 will the power of that Great Being be manifested, who seems to 

 have ordained, that 



" Order is Heaven's first law." 



I beg to remain, in the mean time, my dear Sir, 



Yours, very sincerely, 



Andrew Crosse. 



_ Broomfield, Dec. 27, 1837. 



P. S. Since writing the above account, I have obtained the in- 

 sects on a bare platina wire plunged into fiuo-silicic acid, one inch 

 helow the surface of the fluid at the negative pole of a small bat- 

 tery of two inch plates in cells filled with water. This is a some- 

 what singular fluid for these insects to breed in, who seem to have 

 a flinty taste, although they are by no means confined to siliceous 

 fluids. This fiuo-silicic acid was procured from London some 

 time since, and consequently made of London water ; so that the 

 idea of their being natives of the Broomfield water is quite set 

 aside by this result. The apparatus was arranged as follows : 

 Fig.^ 7, a glass basin (a pint one) partly filled with fiuo-silicic acid 

 to the level 1. 2, a small porous pan, made of the same materi- 

 als as a garden pot, partly filled with the same acid to the level 2, 

 with an earthen cover, 3, placed upon it, to keep out the light, 

 dust, &c. 4, a platina wire connected with the positive pole of 

 the battery, with the other end plunged into the acid in the pan, 

 and twisted round a piece of common quartz ; on which quartz, 

 after many months' action, are forming singularly beautiful and 

 perfectly formed crystals of a transparent substance, not yet ana- 

 lyzed, as they are still growing. These crystals are of the modi- 

 fication of the cube, and are of twelve or fourteen sides. The 

 platina wire passes under the cover of the pan. 5, a platina wire 

 connected with the negative pole of the same battery, with the 

 other end dipping into the basin, an inch or two below the fluid ; 

 and, as well as the other, twisted round a piece of quartz. By 

 this arrangement it is evident that the electric fluid enters the po- 

 rous pan by the wire 4, percolates the pan, and passes out by the 

 wire 5. It is now upwards of six or eight months (I cannot at 

 this moment put my hand on the memorandum of the date) since 

 this apparatus has been in action, and though I have occasionally 



