146 Prof. Johnson's Report 07i the Bradford Coal Field. 



It loses by calcination, - - - - 22.7 per cent. 



And gives of iron, _ _ . - 29.4 



Earthy matter, - - - - - 36.7 



- Volatile matter, oxygen, diC, - - - 11.2 " 



100.0 



" No. 7. This is the middle ply of the ore in the bed near Mason's 

 coal mines. It is found in a stratum of kidney-shaped balls, five inches 

 thick. Its color, in fresh fractures, is dark bluish gray, surface splintery, 

 occasionally giving cd'nchoidal fractures, compact, and of uniform texture. 

 Its specific gravity is 3.763. 



Heated to 320^, it loses but - - - 0.2 per cent. 



Fully calcined, it loses in addition, - - 29.8 



Treated with pure lime, it yields at once malleable 



iron with a little oxide, - - . 45. 



Earthy impurity, - - - - 4.1 " 



Oxygen, - - - - - 10.9 



" This stratum affords the richest ore which has fallen under my notice 

 from any coal formation, for the sample above analyzed was not a surface 

 specimen reduced to the state of a hydrate, but a well marked solid car- 

 bonate, M'ith only a thin surface coating of hydrate. It will probably be 

 found expedient to work it with either No. 1 or No. 3, or with both to- 

 gether, in order to obtain a good soft pig metal. 



"No. 8. This ore is found in the upper of the three bands already 

 mentioned. It generally presents the appearance of nearly square blocks, 

 or brick-shaped masses, seven inches thick. Above this ply of ore, is a 

 course of balls separated from it only by a few inches of friable sandstone. 

 A coarse quarizose grit lies a little higher. The aspect of this ore, when 

 it has not undergone any decomposition by atmospheric influences, is a 

 dark gray color, a rather rough surface, and a mixture of shining metallic 

 particles interspersed through the body of the ore, as well as on its sur- 

 face. Its specific gravity is 3.4783. 



At 320°, it loses, - - - 



At a white heat it undergoes decomposition, and 

 loses, ------ 



It smelts without difficulty, and yields of pig iron. 

 It contains of earthy impurities, fusing into a dirty 



white cinder, - - 



And the oxygen is, - - 



100.0 



"The pig metal obtained was soft, gray and tough. There is no doubt 

 in my mind, that this ore will be found to work well either by itself, or 

 with the other ores found in this bed. 



