1815.] in the Physical Sciences. 15 



there was formed an acid gas resembling sulphureted hydrogen in 

 smell, but possessing very different properties. Water absorbed 

 twice its bulk of it With potash it formed a black insoluble com- 

 pound, not decomposed by any acid. Such were the different 

 results obtained by Mr. Miers. They are highly curious and inte- 

 resting ; but it is obvious that they require to be followed farther 

 before they can be considered as establishing the compound nature 

 of azote, and that it is composed of oxygen and hydrogen. The 

 inconsiitency of the results with each other, the new facts brought 

 to view by every repetition of them ; and, above all, the circum- 

 stance of the gas, in the most decisive of all the experiments, pos- 

 sessing the properties and composition of atmospherical air, lead to 

 suspicions which require to be obviated. It would be requisite, 

 likewise, to account for the sulphur of the sulphureted hydrogen, 

 and to show that the copper tube can have no influence on the de- 

 composition of this gas. 1 hope, therefore, Mr. Miers will resume 

 lus experiments, and prosecute them till he obtains results free 

 from all such anomalies, and leading to conclusions that cannot be 

 controverted. The investigation is indisputably an object of import- 

 ance ; and he h.is made such progress in it, that he ought to enjoy 

 the reputation that would iniallibly result from so interesting a dis- 

 covery. 



5. Pho.fphorw;. — The facts respecting phosphorus, published by 

 Thenard in the Annales de Chimie, had been almost all anticipated 

 long ago by Proust. Hence I conceive it to be unnecessary to detail 

 them here. Heinrich, in his treatise on the phosphorescence of 

 bodies, has stated some facts respecting the temperature at which 

 phosphorus burns in various circumstances, which perhaps may be 

 worth transcribing. When phosphorus is put into the bottom of a 

 narrow glass tube, it may be heated to 482° without taking fire. ]n 

 the open air phosphorus burns at 99°, and in oxygen gas at 72°. I 

 Cannot avoid observing that these detenninations are far from pre- 

 cise. Indeed, nothing definite can be established respecting the 

 combustion of phosphorus, because the degree at which it catches 

 fire depends upon its purity. Pretty pure phosphorus I found did 

 not begin to burn rapidly till heated to the temperature of 148°; 

 but if you keep it long in the temperature of 99°, its temperature 

 gradually increases by its slow combustion, and it will, after a cer- 

 tain time, burn rapidly. According to Heinrich, a compound of 

 equal parts phosphorus and sulphur becomes luminous at ;U)'^. 



6. Ammonia. — The important experiment of Berzelius, who 

 converted mercury into an amalgam, by causing the galvanic 

 battery to act upon it when in contact with ammonia, has not yet 

 been cleared up in a satisfactory manner. It follows from it that am- 

 monia contains a substance of a metallic nature as its l)asc, and that 

 when Uiis base is deprived of oxygen by the influence of the gal- 

 vanic battery tlie metal amalgamates with mercury. On the other 

 hand, the analysis of ammonia by means of electricity, and the 

 resolution of it into hydrogen and aiiote without the least trace of 



