40 STEVENSON— INTERRELATIONS OF FOSSIL FUELS. 



VII. are coking; the high volatile in these last, so greatly beyond 

 that of other coals within the same little area, suggests that perhaps 

 they contain some cannel. The Burrum specimens are all from a 

 very small area, where mining has been carried on extensively and 

 they are from only two seams. II. and III. are from the bottom 

 and top of the Laphani or most important seam. The ash is low 

 throughout, showing that, in this area at least, the conditions were 

 favorable to the accumulation of clean coal. All of the seams yield 

 good caking coal, though they differ in the hardness ; that from 

 several seams is hard shipping coal whereas that from others, espe- 

 cially that from one, is tender and therefore inferior as a steam coal. 

 There is nothing in the structure to explain this difference as the 

 seams are separated by a small interval. The Lapham coal yields 

 10,200 cubic feet of gas per ton, with 14.73 candle power; this is 

 the result of a trial lasting for 20 months. 



The Triassic coal of Norroy, France, was analyzed by Regnault, 

 who obtained 19.20 per cent, of ash. The ultimate composition of 

 the pure coal is : Carbon, 77.23, hydrogen, 5.39, oxygen and nitrogen, 

 17.37. Servier asserts that the specimen was not fairly representa- 

 tive and gives the results of a proximate analysis by himself : Mois- 

 ture, 10.00, ash, 9.20, volatile, 42.4, fixed carbon, 57.5. This he 

 regards as a fair average composition. He thinks it is a transition 

 from brown to stone coal but the distillate is alkaline, not acid. 



The Upper Triassic coals of the Richmond basin are all of high- 

 grade bituminous quality, are caking and for many years they were 

 used in the manufacture of illuminating gas in New York, Phila- 

 delphia and other large cities. The available analyses are those re- 

 ported by W. B. Rogers,*^ which represent the average of the coal 

 as observed at the more important localities. Twenty-two analyses 

 were made. The ash is below 6 per cent, in all except 7 and ex- 

 ceeds II per cent, in only 3. The volatile in pure coal varies from 

 30 to 40 per cent., south from James River, and from 25 to 35 in 

 mines north from that river. Much of the basin is broken by dikes 

 which in some portions have converted the coal into coke ; but 

 there are anomalies not due to the influence of igneous rock. 

 Analyses of samples from the bottom, middle and top of the thick 



*8 W. B. Rogers, " Report of Progress for 1840," reprints, pp. 532-535. 



