Miscellanies. 193 



15. Arsenic in Sea Salt. — The presence of arsenic in sea salt has 

 already been observed in that found in commerce ; and MitI. Latour 

 de Frie and Lefranqois, students in pharmacy, have lately detected it 

 in a salt used in the canton of Sezanne, in the department de la Marne. 

 It appears to have occasioned serious accidents; and vi'^as submitted 

 to examination, which showed that the salts contained a quarter of a 

 grain of deutoxide of arsenic in an ounce. The authors purchased 

 salts in various parts of Paris, but did not detect arsenic in any one 

 sample. — Ibid. 



16. On chloride of Silver ; by M Cavalier. — (Jour, de Pharmacie) 

 — The color produced in chloride of silver by the action of light, has 

 long been known, and a similar change is apparently produced by 

 some chemical reagents; but whether the alterations are identical is a 

 question which M. Cavalier says he does not pretend to decide. He 

 then states a method hy which the violet chloride of silver may be 

 procured without the agency of light. Dissolve some recently pre- 

 pared and perfectly white chloride of silver in ammonia, and pass a 

 current of chlorine gas through it, and the same phenomena as occur 

 when the gas is passed through mere solution of ammonia will be pre- 

 sented ; such as slight detonation on the arrival of each bubble to the 

 surface, abundant white vapors, increase of temperature, the disen- 

 gagement of azotic gas, &c. Afterwards, the solution becomes turbid, 

 and soon a greyish precipitate is observed ; at length it assumes a well 

 marked violet color : this color occurs when the ammonia is com- 

 pletely decomposed by the chlorine. 



What is the nature of this new substance ? Is it a smaller or great- 

 er quantity of chlorine Avhich has modified the properties of the chlo- 

 ride ; or is it identical with the white chloride : and is the color acquir- 

 ed, merely the result of a different molecular arrangement? 



The following experiments are in favor of the latter opinion. 



If the violet chloride be dissolved in ammonia, nitric acid precipi- 

 tates it white. Take 20 grains of violet and 20 grains of white chlo- 

 ride, put each into a glass, and with them diluted sulphuric acid and a 

 piece of zinc, stirring the chloride with the latter so as to keep it sus- 

 pended ; the chlorides are both decomposed by the hydrogen evolved, 

 and metallic silver is obtained, and from each chloride the same quan- 

 tity, vij, 15 grains. 



According to these experiments, the new substance cannot be re- 

 garded either as sub-chloride or a deuto-chloride ; every circumstance 

 seems to prove that the color is produced merely by a difierent mole- 

 cular arrangement. In this case, it remains to be explained what is 

 the body which forces the chloride to acquire a different physical prop- 



VoL. XX.— No. 1. 25 ' 



