288 Analyses of Books. [April, 



1. Those kinds that contain much bitumen. The following 

 table exhibits the maximum quantity of gas obtainable from coals 

 belonging to this class : 



One chaldion of coul produces Cubic feet of gas, 



Scotch cannel coal 19,890 



Lancashire Wiggan coal 19,608 



Yorkshire Cannel coal (Wakefield) 18,860 



Staffordshire coal,* 



First variety 9,748 



Second variety t 10,223 



Third variety '. 10,866 



Fourth variety 9,796 



Gloucestershire coal,t 



First variety (Forest of Dean, High Delph) 16,584 



Second variety (Low Delph) 12,852 



Third variety (Middle Delph) 12,096 



Newcastle coal. 



First variety (Hartley) 16,120 



Second variety (Cowper's High Main) 15,876 



Third variety (Tanfield Moor) .^ 16,920 



Fourth variety (Pontops) 15,1 12 



2. The second class consists of coals containing a smaller 

 quantity of bitumen, and more charcoal than the preceding. 

 The following table exhibits the maximum quantity of gas 

 obtainable from coals belonging to this class : 



One chaldron of coal produces Cubic feet of gas, 



Newcastle coal, 



First variety (Russel's Wall's End) 16,876 



Second variety (Bewick and Craister's Wall's End) . . 16,897 



Third variety (Heaton Main) 15,876 



Fourth variety (Killingsworth Main) 15,312 



Fifth variety (Benton Main) 14,812 



Sixth variety (Brown's Wall's End) 13,600 



Seventh variety (Mannor Main) 12,548 



Eighth variety'(Bleyth) 12,096 



Ninth variety (Burdon Main) 13,608 



Tenth variety (Wear's Wall's End) 14,1 12 



Eleventh variety (Eden Main) 9,600 



Twelfth variety (Primrose Main) 8,348 



3. The third class consists of coals that yield little or no 

 bitumen when distilled. The following table exhibits the maxi- 

 mum quantity of gas obtainable from this class of coal. 



• They require a much higher temperature than is necesfary foj tb* decompoti- 

 tioii of Newcastle coal. 



■i Most varietiee afford a porous and very friable coke. 



