Hardman — On Analysis of Coals and Iron-stones. 

 Indiana Coal-Field.*' 



537 



Specific Gravity. 



Ash. 



M76 



0-3 



1-230 



2-0 to 3-0 



1-264 



2-5 



1-28 



6-5 



1-29 



4-5 



1-32 



6-0 



Ohio. — Block Coal. 



In six analyses the specific gravity ranges from 1-247 to 1*284. 



And the ash. from, 3" 18 to 1.16. 



Apparently reversing the matter. However, both the range of ash 

 and of the specific gravity is very small here. 



Among English and Scotch coals, as well as other Irish coals, a 

 tolerably fair relation seems to exist in this way, as the following 

 examples will show. 



Name of Coal. 



Sp. Gr. 



Ash. 



"WTiere Published. 



Scotcli (Fordel Splint), . 



1-25 



4-0 



\ Coal Fields of Great Britain, 

 j Prof. Hull, p. 406. 



Newcastle (Cans. Hartly, 



1-25 



5-0 



Alfreton, Derbyshire, 



1-235 



2-04 



\ Chemical Technicology. 



,, Cannel, . . . 



1-278 



4-64 



r Drs. Eonald and Eichardson. 



Liverpool Coal, . . 



1-260 



4-62 



1 Vol. i., pt. ii., Analytical 



Newcastle-on-Tyne Birtley 



1-270 



4-00 



; Table, p. 1. 



Ballycastle, Ireland, . . 



1-273 



4-20 



Laboratory Notes, Mus. Ir. Ind. 

 Technicologist. 1864. 



Lough Allen, Leitrim, 



1-336 



7-52 



Do. do. 



Do. do. . . 



1-369 



7-63 



Do. do. 



Do. do. . . 



1-382 



17-7 



L. Studdert, LL.D.," Jour. EL 

 Geo. Soc. I.," Vol. iii.,p. 135. 



So far then, it would appear, that within certain limits the specific 

 gravity of a coal is a tolerably fair guide to the quality of it. For 

 instance, one would not be far wrong ia putting down a coal of 1-35 

 specific gravity as containing over 10 per cent, of ash, while one of 

 1'25 would be almost free from it. 



Iron-stones. — In the shales and fire-clays of the middle series of 

 the Tyrone coal-measures there is a good deal of iron-stones, which 

 ■occur both in beds and nodules, the former, in one or two instances, 



* Op. cit., p. 401. 



