Miscellanies. 369 



Mercaptan is a limpid liq^uid even at +10^, and is destitute of 

 color. Its odor is peculiar, and approaches that of garlic or assa.- 

 foetida ; its taste is sweetish and ethereal; density =0.842, boiling 

 point +111. It is slightly soluble in water, but very much so in 

 alcohol or ether. 



It combines with Potassium, giving up its Hydrogen, and produ- 

 ces a saline mass, colorless and very soluble, which gives a yellow 

 precipitate with the salts of lead, and a white with the deuto-chlorids 

 of mercury, gold and copper. When placed in contact with the 

 deutoxyd of mercury, the mercaptan attacks it with violence, and 

 there is produced a colorless crystalline body, (raercaptid of mer- 

 cury,) together with some water. 



The mercaptid of mercury melts at 187°, commences to change 

 its appearance at 257°, and is decomposed at 347°, with the disen- 

 gagement of thialic oil. It is insoluble in water and alcohol, and is 

 not acted upon by a concentrated solution of potash, and probably 

 not by any of the acids except the nitric. 



The mercaptid of Gold is colorless and destitute of lustre. The 

 mercaptid of Platinum changes into a sulphuret by calcination. 

 The mercaptids of Potassium, Stc, have an alkaline reaction. In 

 a dry state, no change is caused by a heat of 212° : In solution, 

 however, the effect of heat is soon apparent. 



It is very remarkable that the composition of mercaptan corres- 

 ponds exactly with that of alcohol. 



16. Experiments upon the chemical action of the electrical cur- 

 rents produced by the influence of terrestrial magnetism and electro- 

 dynamic magnets, i^'C, by M. Botto, of Turin. (Translated from 

 an extract from the author's work, in the Bib. Univ. des Sciences, 

 &c. Fev. 1835, p. 120. 8vo. Geneva.) — The apparatus by means 

 of which M. Botto has been enabled, through the influence of terres- 

 trial magnetism, to obtain electrical currents capable of exercising a 

 chemical action, consists of two cylindrical bars of soft iron five feet 

 in length and six inches in diameter, each spirally wound with cop- 

 per wire, and set in motion by means of part of the apparatus of an 

 old electrical machine. The opposite extremities of each of the 

 bars, in their revolution, passed before and near those of two pris- 

 matic bars, also of soft iron, ten feet long, ten inches wide, and 

 three inches thick, and placed in the direction of the dipping needle. 

 By means of a galvanometer, the presence of two contrary cur- 



VoL. XXIX.— No. 2. 17 



