SYMPOSIUM ON SCIENCE AND RECONSTRUCTION 93 



is possibly a variation of about 1 per cent in the sulphur 

 content among the coals north of Jackson. Jefferson, and 

 Saline counties, except for Mercer and Rock Island 

 counties. These coals have between 3.25 and 4.00 per cent 

 of sulphur. The Eock Island and Mercer County coal 

 (No. 1) has an unusual sulphur content, varying from 4.25 

 to 5.02 per cent. 



In the southern counties, Jackson, Williamson, south- 

 eastern Perry, Saline, and Gallatin, the sulphur content 

 averages 1 to 2 per cent less than it does to the north, vary- 

 ing from about 1 to 2.75 per cent. In the yellow area, 

 shown on the map in Franklin, Williamson, and Jackson 

 counties, the sulphur content averages below 1.5 per cent, 

 and in the pink area within the yellow, below 1 per cent. 

 The low sulphur content of the southern Illinois coals is 

 one special reason for their greater desirability among the 

 coals of the State for domestic as well as for gas-making 

 purposes. It should be stated, however, that coal from 

 other parts of the State, if properly prepared at the mine, 

 could probably be used with equal satisfaction by the 

 householder, thus reserving the low-sulphur coal for in- 

 dustrial uses, to which it is specifically adapted. 



In general, the low-sulphur coals containing less than 

 three per cent of sulphur do not contain much pyrite in 

 free or nodular form. Veiy little recoverable pyrite is 

 present in these coals. The higher sidphur coals, however, 

 although they all contain free pyrite in some form, do not 

 always contain it in recoverable form. Its ease of recovery 

 may in fact be taken as an index of the ease with which 

 clean coal can be furnished at the shaft head. The ease of 

 recovery, furthermore, can by no means be inferred from 

 the coal analysis, but can be determined only by an inspec- 

 tion of the coal at the face in the mine. 



Most of the pyrite occurs in one of three forms : (Das 

 nodules or balls ; (2). as sheets or thin lenses in the parting 

 between benches; and (3) as lenticular masses fingering 

 laterally into the coal. Coals differ somewhat character- 

 istically in regard to the form of pyrite most commonly 

 found in each bed. Thus, No. 2 coal of northern Illinois 



