RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES. 203 



a fused mixture of sodium carbonate and potassium bichromate, but no sodium sul- 

 phate was produced. Moreover, the gas escaping from the tube possessed the char- 

 acteristic odor of the mercaptan. The same experiment was tried with a mixture 

 of sodium carbonate and sodium nitrate with a similar result. On account of its 

 numerous reactions towards the various metallic salts, a separation of methyl hydro- 

 sulphide and sulphuretted hydrogen is a difficult matter. As it acts slowly and 

 incompletely upon yellow mercuric oxide, this substance may be used to absorb sul- 

 phuretted hydrogen. Although methyl hydrosulphide attacks and combines with 

 the mercuric oxide, sulphuretted hydrogen gradually expels it, the yellow color grad- 

 ually changing to black, owing to the formation of sulphide of mercury. The yellow 

 copper compound changes into copper sulphide. The same is true of the yellow 

 compounds of lead and silver and the white cadmium compound. This change into 

 sulphide is in every case promoted by exposure to air, especially in presence of 

 ammonia. In an aqueous solution of methyl hydrosulphide containing neither acids 

 nor alkalies, the various compounds are more stable. 



The mercaptides are easily produced in many cases by the action of a solution 

 of the mercaptan in water upon the oxides, hydroxides or carbonates of the metals, 

 and when so formed they are easily preserved unchanged. 



It is of importance to note that sulphuretted hydrogen expels methyl hydrosul- 

 phide from many of its metallic compounds. The reactions of CH^SH towards gold 

 chloride and arsenious chloride are especially remarkable. In the former case the 

 production of a precipitate, gradually changing from yellow to white and finally dis- 

 appearing, distinguishes this gas from sulphuretted hydrogen. The formation of an 

 oily liquid insoluble in water, in the case of arsenious chloride, also serves to distin- 

 guish between the two gases. 



METHYL SULPHIDE. 



This compound may be prepared by the action of methyl iodide (or, preferably, 

 methyl chloride) upon potassium sulphide in alcoholic solution. Gaseous methyl 

 chloride may be led into an alcoholic solution of potassium sulphide contained in a 

 flask heated over a water bath and connected with a reversed condenser. The vapor 

 of methyl sulphide thus formed may be freed from sulphuretted hydrogen by oxide 

 of mercury or by passage through warm soda solution. 



In the process of Klason, already described, methyl sulphide is produced simul- 

 taneously with the hydrosulphide. The process yields, in fact, a larger proportion 

 of the former than of the latter. It may be readily separated, as already stated, by 

 means of soda solution, which absorbs and combines with the mercaptan but exerts 



