18 Sketch of the latest Improvements [Jan. 



oxygen, is equally decisive. These two sets of experiments seem 

 at first sight incompatible witli each other, and show us that there 

 is something connected with the nature of azote still unknown. 

 The fact that no substance constitutes a saline base, or is capable of 

 uniting with acids, and forming salts, unless it contains oxygen 

 (ammonia alone excepted), is a strong analogical argument in 

 favour of the existence of oxygen in ammonia. It has accordingly 

 induced Berzelius to enibiace that opinion ; and I must acknow- 

 ledge that it is difficult to resist so very general an analogy. The 

 anomaly respecting the composition of ammonia will be removed 

 completely whenever it is proved in a satisfactory manner that azote 

 is a compound of oxj'gen and hydrogen. This circumstance renders 

 that question of still greater importance than it otherwise would be. 



7. Sulphuret of Carbon. — The properties and constituents of this 

 singular substance, as determined by Drs. Berzelius and Marcet, 

 were stated in our sketch of chemistry given at the beginning of 

 last year. Since that time Berzelius has published additional obser- 

 vations on the combination of sulphuret of carbon with the bases. 

 {Annah of Philosophy, iii. 186.) To these compounds he has given 

 tiie name of carho-sulphurets. The following table exhibits the 

 colour of the precipitates obtained by mixing different metallic 

 salts with a solution of sulphuret of carbon in potash: — 



Muriate of cerium White, or yellowish white. 



Sulphate of manganese . . . .Greenish-grey. 



Sulpliate of zinc White. 



Perniuriate of iron Dark red. 



Submuriate of antimony . , . .Orange. 



Muriate of tin Pale orange, then brown. 



Kitrate of colialt Dark olive-green, at last black. 



Nitrate of lead A fine scarlet. 



Nitrate of copper Dark brown. 



Promuriate of mercury Black. 



Permuriate of mercury Orange. 



Muriate of silver Reddish brown. 



Dr. Brewster has found that sulpliuret of carbon exceeds all fluid 

 bodies in refractive power, and that in this respect it even surpasses 

 flint glass, topaz, and tourmaline. In dispersive power it exceeds 

 every fluid substance except oil of cassia, holding an intermediate 

 place between phosphorus and lialsam of Tohi. 



8. Pofaisi/reted Hydrogen Gas. — Sementini, of Naples, pub- 

 lished, about two years ago, a dissertation on potassium, in which 

 he relates his experiments on potassurcted hydrogen gas, which was 

 discovered by Davy during his experiments on the metal of potash. 

 The following are all the facts tliat 1 can find in these experiments; 

 1. Potassurcted hydrogen gas is heavier tiian pure h3'drogen, and 

 lighter tiian phosphoretcd hydrogen gas. 2. It takes fire, with a 

 kind of explosion, when it comes in contact with the air emitting 

 in alkuiine odour. The explosion is louder when the gas comes in 



