Lesley.] 138 [June, 1871. 
The analyses given above are important. They oppose the law of pro- 
gressive bituminisation westward of the coal beds. 
That both the 6 foot and the 8 foot Ursina beds, situated at the western 
limit of the 1st Bituminous coal basin, should have only 17 per cent. of 
volatile matters,—not more than the coals of the Broad Top Region, 
lying one hundred miles to the east of Ursina,—is truly remarkable. 
The Broad Top beds are tilted and faulted abundantly. The Somerset 
County beds are almost perfeetly undisturbed. The coal in one gangway 
showed 22 per cent. of volatile substances. But even this is no greater 
than the coals of the summit of the Alleghany Mountain, and the coals of 
the Cumberland Coal Region. 
No proper scheme of the rates of debituminisation to casting, and to 
disturbance, can be obtained until all the analyses of each bed in the 
series of Coal Measures shall be tabulated apart from the rest. We may 
then expect to learn something also respecting the influence of specific 
vegetation upon the percentages of coke and gas. 
But in the outset one source of error must be guarded against. The 
specimens of coal from which the foregoing analyses were made, were ob- 
tained in the walls of old gangways. It is possible that they had been 
long enough exposed to the air to lose some of their hydro-carbons by 
spontaneous evaporation. The rate at which this goes on in coal mined 
and exposed in heaps, is variously stated by those who have investiga- 
ted the subject. 
Dr. Richters made a recent communication toa German Journal, in 
which he states his opinion, that the weathering of coal depends upon 
its ability to absorb oxygen, converting the hydro-carbons into water 
and carbonic acid. At a heat, say of 875° F, only 5 or 6 per cent. of the 
carbon accepts oxygen, the rest seems to show little or no disposition to 
affine with it. The process is apparently dependent upon the per cent- 
age of hydrogen. But with coal, cold, or at ordinary temperature, the 
oxydation is so slow as to be imperceptible, even after exposure for an 
entire year. He says moisture has no accelerating effect, unless pyrites 
is present in quantity. Pure coal, heaped up for nine months or a year, 
unprotected by the weather and not allowed to become heated, is changed 
no more than it would be in a perfectly dry place. 
Herr Grundmann, of Tarnowitz, on the other hand, has recently pub- 
lished elaborate experiments proving the effects of exposure on bitumin- 
ous coals to be most serious. Coal which he exposed for nine months, 
lost fifty per cent. of its value as fuel. His conclusions excited such doubts, 
that his experiments were repeated, in connection with Herr Varrentrapp, 
of Brunswick, who proved, by laboratory experiments, that oxydation 
took place at common temperatures. Three months sufficed to rob coal, 
kept uniformly at 140° C. (284° F.) of all its Carbon, a heat less than 
that evolved in coal heaps exposed to the air. 
Grundmann proyed that the decomposition was the same in the middle 
of the heap as at the surface, and reached its maximum about the third 
or fourth week ; that half of the oxygen was absorbed during the first 
fourteen days ; that a coal poor in oxygen absorbs it most rapidly ; that 
moisture is an important condition ; that coals making, when freshly 
mined, a firm, coherent coke of good quality, make, after even only 
eleven days’ exposure, either no coherent coke at all, or coherent coke of 
quite inferior quality. For gas purposes also, the coal is greatly injured. 
It is evident that these facts have an important bearing on the value of 
the analyses given above. 
Sd 
