566 Transactions. — Chemistry and Physics. 



Akt. LV. — On the Apparent Occlusion of Sulphuretted Hy- 

 drogeri in a Bituminous Coal. 



By Dr. W. P. Evans. 



{Read before the Philosophical Institute of Canterbury, 2nd November, 



1898.] 



While pulverising a sample of coal from the Westport- Cardiff 

 Company's Hannah Hector outcrop a distinct odour of sul- 

 phuretted hydrogen was noticed, and a sensitive lead acetate 

 paper held in the mortar was coloured light-brown. This re- 

 sult was the more remarkable as the Westport-Cardiff coal 

 had been proved by repeated analyses to be freer from 

 sulphur than the average hard coal of the West Coast dis- 

 trict. 



The finely pulverised coal lost all trace of the sulphur- 

 etted-hydrogen smell in a few minutes, and then contained 

 0-54 per cent, of sulphur. The coal in question is a fairly 

 hard black coal, very lustrous, and often shows a finely 

 developed conchoidal fracture. It does not soil the hands at 

 all, and contains, as is the case with all the Westport-Cardiff 

 coal, only a very small percentage of ash* (0-62 per cent, as 

 average of many determinations). To the naked eye the coal 

 is, except for the fissures parallel to the bedding-planes, as 

 homogeneous as a coal could be expected to be, and quite 

 unlikely to contain any large cavities filled with gaseous 

 matter. When, however, we remember that even the densest 

 of rock -forming minerals often contain cavities filled with 

 compressed or liquefied gases, there seems no a priori reason 

 to doubt the possibility of such gas-filled hollows existing in a 

 piece of apparently solid coal. 



Sulphuretted hydrogen is certainly formed in large quan- 

 tities by the reduction of sulphates in the presence of organic 

 matter and subsequent elimination of the sulphur from the 

 resulting sulphides. 



That brown coals have the power of absorbing a large 

 quantity of sulphuretted hydrogen is also a well-established 

 fact, and the large percentage of sulphur in many brown coals 

 known to contain but little iron-pyrites has been attributed 

 by Mr. Skey to this absorption of sulphuretted hydrogen. f 

 So far, however, I have not succeeded in finding any recorded 



* For other analytical details see above Art. LIV., " Analyses of New 

 Zealand Coals," No. 18. 



t Appendix A to Jurors' Eeports, New Zealand Exhibition, 1865, 

 p. 369, where several interesting experiments by Mr. Skey are briefly 

 outlined. 



