1864. ] Chemistry. 459 
which retained the fibrous and veined appearance which belonged to 
the original mineral.* The same author has extended his investiga- 
tions to the colouring matter of precious stones with some unexpected 
results. The amethyst, for instance, he finds to be coloured by some 
organic matter, and not by a metallic oxide. For the author’s mode 
of analysing gems of various descriptions, and the results, we must 
refer the reader to the original paper in the ‘Comptes Rendus’ for 
March 28. 
Mr. Sonstadt, who has already achieved distinction as a manufac- 
turer of magnesium, has now turned his attention to calcium, and 
succeeded in obtaining this metal in a tolerably easy way.t He first 
fuses together iodide of potassium and chloride of calcium, and then 
adds the mixture to sodium, and continues the heat, which need not 
be great. This, as the author states, is only a modification—in which, 
however, a serious obstacle is avoided,—of the method proposed by 
Liés Bodart, and Bodin. 
Lastly, in the department of inorganic chemistry, we must notice 
the production by M. Peligot of some useful alloys of silver and zinc. 
The French Government is about to reduce the standard of the silver 
coinage, which disappears from circulation in consequence of the 
scarcity of the metal. M. Peligot, who is chemist to the French Mint, 
suggests that zinc should be employed in the alloy instead of copper. 
One great recommendation of such an alloy is, that it does not blacken 
when exposed to sulphur compounds, nor furnish verdigris with acid 
liquids ; it is therefore especially applicable for watch cases, jewellery, 
and coins. The best alloy we may say is composed of eight parts of 
silver and two parts of zinc. 
Among the recently published results of investigations in the 
domain of organic chemistry, we may notice those of Cahours and 
Frémy on the respiration and maturation of fruits.{ Cahours experi- 
mented upon apples and oranges, and found that when placed in a jar 
of oxygen or in mixtures of oxygen and nitrogen, the fruits absorbed 
the former gas and evolved carbonic acid. This went on and increased 
rapidly as the fruit ripened. In the expressed juices of the fruits he 
found carbonic acid and nitrogen, but not oxygen, hydrogen, or car- 
bonic oxide. Further than this, he found that when the same fruits 
were placed in nitrogen or hydrogen, they still evolved carbonic acid, 
and the ,volume of the external gas increased. Hence the carbonic 
acid must have been produced by changes within the fruit and inde- 
pendent of the external atmosphere. The internal changes have been 
shown by MM. Chatin, Frémy, and Decaisne to consist in the oxida- 
tion of the immediate soluble principles. Tannin, it would seem, dis- 
appears first, then the acids, and lastly the sugar. These changes are 
well illustrated in the case of the medlar, which, when gathered, is 
very acid and astringent, and only becomes eatable after having been 
kept for some time in the air. 
* «Comptes Rendus,’ May 17. 
+ ‘Chemical News,’ vol. 1x. p. 140. 
t ‘Comptes Rendus, various, March, April, and May. 
VOL, I. IAT 
