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Miscellanies. 193 
15. Arsenic in Sea Salt-—The presence of arsenic iti sea salt has 
alteady been observed in that found in commerce ; and MM. Latour 
de Frie and Lefrangois, students in pharmacy, have lately detected it 
ina salt used in the canton of Sézanne, in the department de la Marne. 
It appears to have occasioned serious accidents; and was 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 arsenie in any one 
sample. bid. 
‘16, On chloride of Silver ; by M Cavalier.(Jout. de Pharmacie) 
—The color produced in chloride of silver by the action of light, has 
long been known, artd 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 
en states a method by 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 cém-< 
Pletely decomposed by the ehlorine. 
hat is the nature of this newsubstance? Is it a smaller or great- 
€r quantity of chlorine which has modified the properties of the chlo- 
€} or is it identical with the white chloride: and is the color aequir- 
ed, merely the result of a different molecular arrangement? 
€ following experiments are in favor of the latter opinion. 
If the violet chloride be dissolved in ammonia, nitrie 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 
Plece 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 éach chloride the same quan- 
hty, viz. 15 grains. 
According to these experiments, the new substance cannot be re- 
sarded either as sub-chloride or a deuto-chloride ; evéry circumstance 
*eems to prove that the color is produced merely by a different 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- 
=f 0t. XX.—No. 1 25 
