TRANSACTIONS OF THE SECTIONS, 4^7 



Electrical Experiments. By Andrew Crosse, Esq. 



Mr. Crosse gave an account of some experiments which he had made 

 on the effect of long-continued galvanic action of low intensity in 

 forming crystals and other substances analogous to natural minerals. 

 At the time when he first commenced these experiments he had not 

 heard of those by which M. Becquerel had previously arrived at similar 

 results. A few weeks afterwards he was informed by a friend that that 

 philosopher had produced sulphurets of lead and silver by electric ac- 

 tion, but his account of the mode of conducting his experiments had 

 not been seen by Mr. Crosse. " It is but due to myself," Mr. Crosse 

 adds, " to mention that I attended the meeting at Bristol without the 

 least intention of intruding on the notice of the Association, well know- 

 ing how incomplete my experiments were ; and had it not been for the 

 advice of some friends whom I met there, I should not have presumed 

 to offer any communication till I had gone further into the matter." 



Mr. Crosse stated that by passing a galvanic current from batteries 

 with various combinations of plates excited by water only, through so- 

 lutions of carbonate of lime, he obtained rhomboidal crystals of that 

 substance deposited round the negative pole. Having in one of these ex- 

 periments kept a piece of scouring brick moistened with the solution for 

 four or five months, at the expiration of that time he found very fine 

 prismatic crystals (which he took for arragonite) deposited on that part 

 of the brick which lay contiguous to, without actually touching, the 

 positive pole, whilst what he considered as common carbonate of lime 

 was confined to the negative pole. In a similar experiment made on 

 fluo-sihcic acid, after a deposit of lead at the negative pole, minute 

 crystals, which he considered as siliceous, made their appearance at the 

 extremity of the deposit of lead, and, on the removal of the lead, at the 

 positive pole : a crystal which was a transparent hexahedral prism ter- 

 minated with a similar pyramid, but which however M'as too soft to 

 scratch glass, was removed at the end of two or three months from the 

 bottom of the piece of brick ; a second well-formed crystal, measuring 

 Yg of an inch in length by j^ in breadth, after being put in a dry place 

 for one or two months, scratched glass readily. Mr. Crosse made simi- 

 lar experiments on solutions of sihcate of potash and obtained imperfect 

 hexahedral crystallizations, which he judged to be siliceous, and in some 

 instances chalcedonic deposits. The foUovdng is a list of mineral sub- 

 stances which he considered himself to have formed by electrical action 

 in addition to those above-mentioned : — Red oxide of copper in octa- 

 hedrons opake and transparent, crystals of copper and silver in cubes 

 and octahedrons, crj'^stallized arseniate and carbonate of copper, phos- 

 phate and grey sulphuret of ditto, sulphuret of silver, crj^stallized 

 carbonate of lead, yellow oxide of lead, mammillated carbonate of lime, 

 oxide of lime, mammiUated black oxide of iron, sulphuret of iron, sul- 

 phuret of antimony (Kermes mineral), crystallized sulphur. 



Between three and four years ago Mr. Crosse made a set of experi- 

 ments on the voltaic battery, and found the power to be considerably 

 increased when each copper plate of the one pair was brought into all- 



