Prof. Wohler on inflammable. Siliciuretted Hydrogen. 521 



tion must be performed with boiled-out water; for with water 

 containing air, the gas soon becomes cloudy and loses its spon- 

 taneous inflammability. The gas may be transferred to a jar over 

 mercury, and at the same time dried, by collecting it in a jar 

 with a stopcock, to which is attached a chloride of calcium tube, 

 and a delivery-tube as narrow as possible. At first the gas 

 takes fire in the tube which still contains air, and then burns at 

 the mouth. It is then inserted under the mercuiy-jar. 



Each bubble of the gas on issuing into the air takes fire with 

 a violent explosion, and the resulting silica forms beautiful 

 annular clouds. Issuing from a narrow tube into the air, it 

 burns with a large, brilliant, white flame. Passed through a 

 gently heated glass tube, it is readily decomposed, and the sides 

 of the tube are covered with a mirror of reduced silicon. It also 

 forms a mirror when its flame burns against a porcelain plate. 

 Notwithstanding its great inflammability, the gas prepared by 

 the above process contains a large quantity of free hydrogen, 

 altliough less than that prepared by the electrolytic process. 

 The gas precipitates solutions of sulphate of copper, nitrate of 

 silver, and chloride of palladium. The copper and silver are 

 precipitated as siliciurets, and the palladium is reduced to the 

 metallic state. 



The substance which yields the gas exists in the slag in the 

 form of small particles, or very small globules. By effecting the 

 reduction with the addition of fluor-spar at a very high tem- 

 perature, a small proportion of dark iron-gray fused masses 

 were obtained. With hydrochloric acid they gave off inflammable 

 gas, leaving a residue of crystallized silicon and dense oxide of 

 silicon*, the formation of which on the surface of the mass soon 

 prevented the liberation of gas. But when these masses reduced 

 to powder were digested with sal-ammoniac solution, spontane- 

 ously inflammable gas was liberated with great energy, and the 

 solution contained magnesium. A gray metallic powder was 

 left, which, treated with hydrochloric acid, gave off" hydrogen, 

 and left a residue of crystallized silicon and oxide of silicon. 

 The metallic masses appear, therefoi-e, to be a mixture of three 

 substances, — of free silicon, of a siliciuret of magnesium, which 

 yields with hydrochloric acid siliciuretted hydrogen, and of a 

 siliciuret of magnesium, which forms with hydrochloric acid free 

 hydrogen and oxide of silicon. The latter substance is con- 

 tained in large quantity in the foam formed in the preparation 

 of the gas. 



In one preparation made on a large scale, small black, metallic, 

 crystalline globules were obtained, an analysis of which gave 

 numbers agreeing with tlie formula Si Mg^. If this decom- 

 * Plul. Ma-. June IH.W. 



