APPENDIX. 
543 
In analyzing a portion of the bituminous schists from the property of the 
Earl of Caithness (near Barrogill Castle), Dr. Hofmann reported to me as fol- 
lows : — " When submitted to the action of heat, this substance evolves a consi- 
derable amount of gas, and likewise of oily matter containing a certain propor- 
tion of ammonia. The residue which remains behind is a greyish mass, consist- 
ing essentially of silicate of alumina (clay) mixed with a certain quantity of 
sesquioxide of iron and of sulphate of lime. A very minute proportion of phos- 
phoric acid was likewise found to be present. The loss which the mineral 
undergoes on heating was found in two consecutive experiments to be 30-21 and 
3O02 ; so that the mineral may be said to contain in round numbers- 
Fixed matter (mineral) 70 
Volatile matter (organic) 30 
100 
" In determining the amount of gas furnished by the distillation of the mineral, 
a portion of it was heated in an iron tube, in order to imitate, as nearly as 
possible, the circumstances of an operation on a large scale. In two consecutive 
experiments which were performed in this manner, the following results were 
obtained : — 
Cub. centim. 
I. 100 grammes furnished 7690 
H. „ „ „ 7430 
Mean 7560 
"Assuming 100 grammes of the mineral to yield, on an average, 7500 cubic 
centimetres of gas, a ton of the material would furnish 2690 cubic feet. The 
ordinary varieties of coal used in gas-making yield from 8000 to 10,000 cubic 
feet of gas per ton. The gas obtained from the mineral is very luminous j it 
is nearly entirely free from sulphur, and it is on this account very readily puri- 
fied. The residue left in the retort after the expulsion of the gas retains but a 
small amount of carbon, viz. 8*5 per cent. ; this residue, therefore, has but little 
value as coke. 
" The mineral in question is in no way related to ozokerite, as has been sug- 
gested. From that substance it may be at once distinguished by its infusibility 
(ozokerite fuses at 80° C. = 176° Fahr.), and by its entire insolubility in alcohol 
and ether, in which solvents ozokerite dissolves, although with difficulty." 
I. — Fossil Reptiles in the Carboniferous Shales of Ireland. 
For a full account of the remarkable evidences of Reptilian life having flourished 
in the Carboniferous period, referred to at p. 303, see the memoir ' On a Collec- 
tion of Fossil Vertebrata, from the Jarrow Colliery, County of Kilkenny, Ire- 
land,' by Thomas H. Huxley, F.R.S. &c, and E. Perceval Wright, A.M. &c, 
Transactions Roy. Irish Acad. vol. xxiv. 1867. 
K.—Spitzbergen (pp. 323 & 368). 
Since Chapter XIV. was printed, I have perused with much interest an excel- 
lent sketch of the geology of Spitzbergen by Mr. A. E. Nordenskiold, resulting 
from the examination of the late Swedish Scientific Expedition*. He sub- 
* Sketch of the Geology of Spitzbergen by A. E. Nordenskibld : Stockholm, 1866. (Transactions of 
the Royal Swedish Academy of Sciences.) 
