Chemical Science. 211 



the combustion dazzles the eyes, and the mass left is more or less 

 fused; the fused particles are yellowish, hard as corundum and 

 cut glass. 



Aluminum is not oxidized by water, unless it be near the boiling 

 point ; then slow action takes place, and hydrogen is liberated. 

 Cold sulphuric and nitric acids do not act upon it ; hot concentrated 

 sulphuric acid dissolves it without the evolution of sulphurous acid. 

 The sulphuric solution did not by evaporation give the smallest 

 crystal of alum. Solution of potash or ammonia cause oxidation of 

 the aluminum, evolve hydrogen, and dissolve the earth formed. 

 Aluminum heated in chlorine inflames, and chloride of aluminum 

 isublimes. 



Sulphur and aluminum combine at high temperatures to form a 

 black semi-metallic sulphuret, which, by the action of water, evolves 

 sulphuretted hydrogen, and leaves gray alumina. Sulphate of 

 alumina cannot be reduced by hydrogen into a sulphuret. 



A similar compound of phosphorus may be formed in a similar 

 way, and has similar appearances. It is also decomposed by water, 

 but not rapidly. A seleniuret, an arseniuret, and a telluret may be 

 formed in the same way. 



The chloride of aluminum and sulphuretted hydrogen combine, at 

 an elevated temperature, and a very white sublimate is formed, partly 

 in transparent pearly scales, and partly as a brittle mass. In the air, 

 sulphuretted hydrogen is evolved, water attracted, and a chloride of 

 aluminum remains in solution ; by heat, from 30 to 40 volumes of 

 sulphuretted hydrogen appear for one volume of the compound, and 

 much must still be retained, as the affinity is exerted only at a high 

 temperature. — Hensman's Repertoire, — Phil. Mag. N. S., iv. 148. 



20. Chloride of Glucinum. — (Ersted showed generally that chlo- 

 rides might be obtained by passing chlorine over an oxide and char- 

 coal heated together, and in that way obtained a chloride of alumi- 

 num, from which the base aluminum has since been obtained. Rose 

 has formed the Chloride of Glucinum by the same process. It very 

 much resembles the chloride of aluminum, sublimes in white floculi 

 having a silky lustre, is fusible by a low heat into brown drops, and 

 is soluble in water. 



^1. Metallic Cerium^M. Mosander. — Previous to the time of M. 

 Mosander, metallic cerium had not been obtained ; and being ob- 

 tained, it proves to be a substance nearer to the earthy than to the 

 ordinary metals, for it decomposes water even at low temperatures. 

 Whefher it is a metal at all or not seems doubtful, if it be, as M. 

 Mosander states, a non-conductor of electricity. He obtains it by 

 decomposing the chloride by the vapour of potassium ; a layer of 

 sulphuret of cerium is put into a glass tube, heated, and converted 

 into a fusible white chloride of cerium, by passing chlorine over 

 it at a high temperature. The volatile matters are theu swept 



P 2 



