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 pia- 

 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. 



' After these experiments, it appears,' says Mr. Matteuci, ' that 

 we may affirm w:ith 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, he. of the 

 oxides of the metals present. — Id. 



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, &lc. 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. — Id, 



8. WhewelVs 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 3C+2S by C^ S^, he. Now this 

 notation is in the highest degree inconvenient, besides violating all 



Vol. XXL— No. 2. 47 



