Page:Transactions NZ Institute Volume 15.djvu/478

from 7 feet to 17 feet, those which have heen worked hitherto being all 12 feet thick or over. Two mines are at present at work here, but another which has been sold will, it is probable, be shortly at work again, and a new company is being formed to open up another lease. The average composition of these coals is as follows:—

There is also a small deposit of coal at Kanieri in Westland, of which the composition is—

and outcrops are also known farther south near the Paringa Eiver, but no work has been expended in opening them up.

The question of the evaporative power of the different coals is now receiving the attention of the department, since it has been found that the number which theoretically represents the number of pounds of water which can be converted to steam, by the combustion of a pound of each coal, is only approximately true for the hydrous varieties, giving them a higher theoretical power than in practice they are found to possess.

Bituminous Peat.—Chatham Islands. This mineral is described (Col. Mus. and Lab. Reports, iii., p. 11) as follows:—

"Colour, black; somewhat vesicular, otherwise very compact; lustre, rather dull generally, bright jet on margins of vesicles. Burns freely to a white ash with much flame; when once set fire to, all the carbonaceous matter is consumed without re-ignition. Does not cake; powder of mineral brown; ash, alkaline; sulphuretted hydrogen cannot be detected in its smoke.