J 8 17. J On a new kind of Coal r , being Volcanic Coal. 371 



separate the graphites from the anthracites ; namely, that with nitre, 

 at a heat a little above its melting point only, the former melt and are 

 consumed, while the latter deflagrate and almost explode. My trials 

 were made with graphite from Borrowdale, from Cochin and from the 

 Himalaya, all of which, as above stated, diffused themselves over the 

 nitre and were consumed gradually, while Newcastle Coal, American 

 Anthracite and our present mineral deflagrate smartly. 



It is usually taken, on the authority of Berzelius, founded on Kar- 

 sten's researches, that the iron in graphite is a mere fortuitous mixture ; 

 but Beudant acutely says* alluding to this, that " when the iron is 

 wanting we have no graphite, and when this substance is found in our 

 furnaces, the proportions are sensibly the same," i e. about 8 per cent, 

 which he seems to think may be the true proportion. I do not advert 

 to Kirwan's experiments, which were merely relating to coal and not to 

 coal and graphite in comparison with each other. . 



In Professor Vanuxem's experiments (Phil. Mag. for September 

 1845) the quantity of manganese and iron in anthracites is stated to be 

 from 0.2 to 7-10 percent, and the water from 4.90 to 6.70. In the 

 graphites he found from 1.40 to 3.60 per cent, of oxide of iron and 

 manganese in the pure, and 20.00 per cent, in the impure kinds ; and 

 of water from 0.60 to 1.23 in the pure and 5.33 per cent, in the impure 

 kinds. 



It may then be a mooted point to which of these two classes of the 

 anthracineaf our mineral belongs, but as I have found nothing of the 

 kind described before I have given it a distinguishing name, to be 

 adopted or rejected, as better authorities shall determine. 



On a new kind of Coal, being Volcanic Coal, from Arracan, by 



the same 



This coal was sent us from Kyook Phyoo by Major Williams, as one 

 of the products of the eruption of the Mud Volcano at that station, 

 described in his letter in the Proceedings for November, 1846. 



It is in two lumps, which look externally like rolled boulders of Coal, 

 and feel greasy on the outside like graphite! 



* Beudant Minerolog-ie, p. 404. 



t 1 use here Mr. Dana's term for this order. 



