334 Analysis of Scientific Books. 



Proto-muriate of tin converts the molybdic into the molybdous 

 acid ; and therefore occasions with it, and molybdate of potash, a 

 characteristic blue precipitate. 



Nitrate of silver is capable, according to Bergman, of detecting 



Tg ^ of common salt in water ; after standing some time, it 

 would discover a much smaller quantity. According to M. Pfaff, 

 proto-nitrate of mercury is a still more sensible test of muriatic 

 acid. One part of muriatic acid, specific gravity 1.15 (equivalent 

 to 0.283 of chlorine) diluted with 70.000 of water, is scarcely 

 rendered feebly opalescent by the nitrate of silver ; and when the 

 dilution amounts to 80000, the effect is null. But the sensibility 

 of proto-nitrate of mercury is such that even sq-q'^'So ^^ niuriatic 

 acid at 1.15, is indicated by a slightly chill shade in the water. 

 MM. Payen and Chevallier maintain the superior delicacy of the 

 silver test. 



Proto-nitrate of mercury is said by Pfaff to be the most delicate 

 re-agent for ammonia; one part of this alkali, diluted with 30000 

 of water, is indicated by a faint blackish-yellow shade, on adding 

 the mercurial solution. Proto-nitrate of mercury may also be 

 used for detecting phosphoric acid ; the precipitate being re- 

 dissoluble in nitric or phosphoric acid, which chloride of mercury 

 is not. 



Nitrate of silver serves to distinguish kinic from the other vege- 

 table acids. The salts of the first acid do not disturb the trans- 

 parency of the nitrates of silver, mercury, or lead. One grain of 

 oxalic acid, according to Bergman, detects one grain of lime in 

 42250 of water. Oxalate of ammonia is, however, the suitable 

 form of applying this test ; MM. Payen and Chevallier say that it 

 is sensible to ,^^\ ^ -g- of lime. 



In the seventh chapter of their treatise, where vegetables and 

 animal re-agents are described, we find the following table of the 

 solubility of some fixed oils in alkohol of specific gravity 0.817, 

 at the temperature of 54°. 5 F. 



Oil of sweet almonds 0,003 



Beech mast . . . 0.004 



Linseed .... 0.006 



Hazel-nuts . . . 0.003 



Common nuts . . 0.006 



Olives ..... 0.003 



Poppies .... 0.004 



Ditto, one year old . 0.008 



In applying starch as a test of iodine, if the latter be combined 

 with a base, we must liberate it by the addition of an acid, as the 

 muriatic. After this, ^^5^^^7t of iodine may be rendered manifest 

 by a violet or purple colour. 



Animal charcoal deprives vegetable juices not only of their 

 colour, but also removes the whole lime which they may contain ; 



