454 M. Wohler on Cerium. 



not strongly luminous flame, forming carbonic and sulphuric 

 acids. If a lighted taper be dipped into the gas, the gas is in- 

 flamed but the taper extinguished, as with a jar of hydrogen the 

 mouth of which is held downward, With 1J volume of oxygen 

 it forms an explosive mixture. 



Potassic hydrate and other alkaline hydrates absorb the gas as 

 completely as carbonic acid, though somewhat more slowly. The 

 solution is inodorous, but disengages sulphuretted hydrogen and 

 carbonic acid when treated with acids. It is probably decom- 

 posed as follows : — 



€OS + 4KHO=K 2 €0 3 + K 2 S + 2H 2 0. 



The solution gives with ammoniacal solution of silver a copious 

 black precipitate, and the filtered solution indicated no trace 

 either of chlorine or cyanogen. 



Neither chlorine nor fuming nitric acid exert any action on the 

 gas at ordinary temperatures. When sodium is heated in the gas 

 it burns with a dazzling light, forming a black easily fusible mass, 

 which consists of carbon, sulphide of sodium, and carbonate 

 of sodium. By heating, the gas is decomposed into sulphur and 

 carbonic oxide without any change of volume. 



The analysis of the gas left no doubt as to its composition 

 being €08, according to which its molecular weight is 60. Its 

 theoretical density according to this is 2*08, while the density 

 observed was 2*109. 



Than thinks that this gas is pretty widely distributed in nature. 



The following observations on the preparation of metallic cerium 

 have been made by Wohler*. A solution of ordinary brown oxide 

 of cerium in hydrochloric acid was evaporated to dryness with an 

 equal quantity of chloride of potassium and of sal-ammoniac; 

 the mixture was then heated in a crucible until all the sal-ammo- 

 niac was volatilized ; and the mass, having been allowed to cool, 

 was broken in small pieces ; and having been mixed with metallic 

 sodium, the mixture was projected into a red-hot crucible. On 

 raising the heat a crackling noise was heard, which indicated a 

 reduction ; the action of the Are was continued until all the so- 

 dium had been volatilized and the mixture was perfectly fluid. 

 On cooling, the dark-grey mass was found to contain numerous 

 small metallic globules. 



These appeared to consist of metallic cerium. Its colour is 

 between that of iron and that of lead, and when polished it dis- 

 plays a tolerably strong lustre. It is malleable, and can be cut 

 almost as easily as lead. Its specific gravity is about 5*5. It 

 gradually loses its lustre on exposure to the air, acquiring a blue 



* Liebig's Annalen, November 1867. 



