and on the Sulphur ets of Lime » 165 



In 1822 Berzelius published a memoir on the alkaline sul- 

 phurets. The results of his experiments seemed to him con- 

 firmatory of the previous notion of Vauquelin. Those ex- 

 periments were on the sulphurets of potash and lime made in 

 the dry way ; he made only one on lime, which agreed very 

 well with the theory; but this very delicate experiment was not 

 enough to establish so important a law of combination, and 

 I do not find that any one besides has obtained the same re- 

 sult *. 



Though I am not prepared to deny that sulphurets of po- 

 tassium and calcium can be obtained by the process of Ber- 

 zelius, I am quite satisfied that sulphurets of potash and lime, 

 &c. may be easily procured in the dry way: of that of lime 

 I have had numberless instances. As the compounds of sul- 

 phur and the alkaline earths have been very little subjected 

 to investigation by chemists in general, we find great vacancy 

 in the accounts grven of them by the modern compilers of 

 chemical books. For this reason I shall introduce here a 

 few of the results I have obtained in a long series of experi- 

 ments on this branch of chemical inquiry. 



Sulphuret ofLime^ in the dry way. 



In 1806 I formed, for the first time, the protosulphuret of 

 lime by heating 50 grains of fallen lime with 50 sulphur in a 

 covered crucible not quite air-tight, so that the escape and 

 combustion of the excess of sulphur might be allowed ; when 

 raised to a red heat an addition was made to the weight of 

 the lime ; by repeating the dose of the sulphur and heating, 

 a further addition was made to the weight ; but repeating the 

 operation a third time seldom made any further addition. The 

 weight of the compound was 65 grains ; it was a white powder 

 with a tinge of yellow, not caustic, but bitter to the taste. 



In 1809 I examined this powder more minutely, and found 

 it was best made by mixing equal weights of pure hydrate of 

 lime and flowers of sulphur, putting the mixture into a covered 

 crucible and heating it slowly to red ; when the escape of the 

 sulphur fumes ceases, cool the contents, and again mix them 

 with the same weight of sulphur as in the first operation, and 

 again heat it as above ; at last it will be found that 32 parts 

 of hydrate of lime = 24- lime have combined with 14 of sul- 

 phur, or one atom to onef. In the work referred to I have 

 stated that pounded lime and sulphur scarcely form any union 

 by this process, and carbonate of lime and sulphur still less. 



* Annals of Philosophy, 1822. 



t See New System of Chemical Philosophy, vol.ii. pages 99 and 102. 



