1854.] Examination and Analysis of four specimens of Coal. 3$ I 



e. The diameter of cyclones undergoes modifications (under 

 certain circumstances) as they advance. 



f. The circular motion is sometimes lost immediately prior to 

 their breaking up, as in No. 17. 



g. But in other instances the cyclones break up, or seem to dissolve 

 themselves, without any particular attendant phenomenon, as in 

 No. 14. 



Such then are some of the deductions that I have been induced 

 to draw from such observations as I have had an opportunity of 

 making, and I beg now to present them for comparison with those 

 of other observers of this interesting branch of meteorological 

 science. 



Examination and Analysis of four specimens of Coal from the neigh- 

 bourhood of Darjeeling ; forwarded by A. Campbell, Esq., Super- 

 intendent. — By H. Piddington, Esq. Curator, Museum Economic 

 Geology. 



No. I. Splint Coal. 



From the bed of a small stream ivhich falls into the Chawa Nuddee 

 three miles above its junction ivith the Teesta. 



This coal is difficult to describe. In the mass the fracture would 

 be, I think, laminar, dividing into rhomboidal parallelopipeds ; the 

 smaller pieces incline to rhomboids, as does the fracture, which may 

 be called hackly and cubical, sometimes very bright and bituminous- 

 looking, and even slightly pavonine in spots ; at others with a strong 

 ferruginous tarnish, which on the weathered surface becomes a thin 

 coating of peroxide of iron. On some of the dividing joints and 

 planes the coal is finely striated, and at some of the fractures it 

 assumes the appearance of closely compressed columnar or globular 

 masses as described by me in my report of the month of April, 

 1853, (Journal, p. 313), on Dr. Campbell's first specimen of coal from 

 Darjeeling. 



It does not soil the fingers, and is very brittle, but hard to pound, 

 for it is long before it can be reduced to the state of coarse shining 

 cannon-powder, and requires hard rubbing to reduce ifc to a fine 

 powder ; but even this is not the sooty powder of the bituminous 



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