Miscellanies. 369 
by one of silver, it soon became covered with a yellow film gradually 
changing to violet, which was considered as chloride of silver. The 
experiment was repeated with the iodides of zinc and iron; the pla- - 
tina poles had scarcely touched the solutions before the iodine, with 
its distinctive color, appeared at the positive pole, and the metals 
were reduced, and deposited upon the negative pole. 
‘Afterthese experiments, it appears,’ says Mr. Matteuci, ‘ that 
we may affirm with certainty, that these combinations, even when 
dissolved in water, do not change in their nature, and are not con- 
verted, as is often imagined, into muriates, hydriodates, &c. of the 
oxides of the metals present.—Jd. 
7. On discolored Chloride of Silver.—(M. Cavalier.)—Chloride 
of silver blackened by sun-light is perfectly well known. M. Cava- 
lier obtains it in a similar state by dissolving the recent chloride in 
ammonia with elevation of temperature, evolution of azote, &c. takes 
place, and ultimately the liquid becomes turbid, and the chloride of 
silver appears first as a grey, and then, when the ammonia is entire- 
ly decomposed, as a violet precipitate. 
This precipitate dissolves entirely in ammonia, and is precipitated 
in a perfectly white state by pure nitric acid. If twenty grains of it 
be decomposed by zinc in dilute sulphuric acid, it yields fifteen grains 
of white chloride. Hence the difference of the chloride in these 
two states cannot be referred to difference of composition, but solely 
to some variation in molecular arrangement.—IJd. 
8. Whewell’s written nomenclature for Chemical Compounds.— 
Extract from Professor Whewell’s Essay on Mineralogical Classifi- 
cation and nomenclature :—Professor Whewell’s mode of designa- 
ting the combinations of chemical elements is different from that of 
Berzelius and of Beudant, but the alterative seems to be absolutely 
necessary. According to their method, the first combination of ele- 
ments into binary compounds is indicated by writing the symbols to- 
gether, without any connecting sign; as if they were algebraically 
multiplied : and the number of atoms of each element is denoted by 
figures written as indices of powers generally are. Thus C+2c they 
would represent by Cc?, and 3C0+28 by C3 S*, &e. Now this 
hotation is in the highest degree inconvenient, besides violating all 
Vor. XXI.—No. 2. 47 
