Chemical Science. 385 



fegulated, by raising or lowering tlic zinc. Every grain of the 

 metal furnishes nearly a cubic inch of the gas, while the ammonia, 

 which also escapes, becomes wholly condensed as soon as it enters 

 into the water of the pneumatic cistern *. 



10. ACTION OF MIXED NITRATE AND MURIATE OF AMMONIA 

 ON GLASS. 



When equal parts of these salts are mixed and fused between two 

 watch-glasses, the under glass becomes corroded nearly to one-half 

 of its thickness, and the eft'ect even extends to the cover. The heat 

 of a spirit-lamp is quite sufficient for this purpose. Here, without 

 water, or even perfect fusion, the alkali is entirely removed, and the 

 silex left, forming a snow-white opaque substance, so soft as to admit 

 of being cut through with the point of a needle or knife : green glass 

 is not so easily affected, owing to its greater hardness and the 

 absence of lead. The fused nitrate alone, if confined between watch- 

 glasses, also produces slight corrosion, but the effect is so remark- 

 able when the nitro-muriate is employed, that a person operating 

 upon an unknown mineral, and ignorant of this property, would 

 be induced to attribute the result to the presence of fluoric acid. 

 Indeed, when we consider that the effect appears to depend upon 

 the liberation of nitro-muriatic acid, or perhaps even to highly con- 

 centrated nitric acid alone, it does not seem improbable that similar 

 cases have often occurred by the common mode of analysing ; and 

 this opinion is further strengthened by the fact, that some minerals, 

 as the chondrodite, appear to have furnished fluoric acid to one 

 operator and not to another f. 



11. PULVERIZATION OF PHOSPHORUS. (CasasecaJ) 



If phosphorus be put with alcohol into a bottle, and shaken for 

 some time, it may be obtained in powder of the utmost tenuity, 

 which, when diffused through the alcohol, appears as if it consisted 

 of a multitude of minute crystals. 



12. INFLAMMATION OF PHOSPHORUS BY CHARCOAL. 



Dr. Bache, of Philadelphia, states, that, at the temperature of 60 R, 

 or upwards, carbon in the form of animal charcoal, or lampblack, 

 causes the inflammation of a stick of phosphorus powdered with it ; 

 the effect takes place either in the open air, or in a close receiver of a 

 moderate size {. 



13. PREPARATION OF BI-CARBONATE OF SODA. 



The following method of preparing this salt, in the large way, is 

 described by Mr. F. R. Smith, of Philadelphia. The ordinary crys- 



* Silliman's Journal, xviii. p. 259. f Ibid, xviii. p. 258. 



J Sillimaii's Jouroal, xviii, p. 373, 



