of Edinburgh, Session 1864 - 65 . 377 
gravity, 1250 to 1300 ; ash generally light like that of wood ; colour 
various shades of white, gray or buff; coke dull to iridescent. 
yil. Chemical Constitution. — The following, which is the mean 
(in round numbers) of numerous analyses, by various chemists, of the 
Tertiary coals of different parts of the New Zealand Islands, may he 
held to represent their average composition : — 
a. Proximate Constituents — 
h. 
Coke, ..... 
45 per cent. 
Carbon in coke (or fixed carbon). 
40 „ 
Volatile matter (hydro-carbons), . 
45 „ 
Ash, ..... 
6 „ 
(Components — Silica, alumina, iron. 
magnesia, and lime.) 
Water of constitution. 
15 „ 
Gfas, cubic feet per ton. 
4000 
Oil,, gallons per ton, 
15 
Ultimate Elements — 
Carbon, ..... 
60 per cent. 
Hydrogen, .... 
Nitrogen, ..... 
1 „ 
Oxygen, ..... 
20 „ 
Sulphur, ..... 
2 „ 
VIII. Commercial Value. — The following are defects in most, if 
not all, of the Tertiary coals of New Zealand ; — 
a. Proportion of water or moisture they contain : frequently 
20 to 30 per cent. 
h. Comparatively large amount of ash. 
c. Comparatively large amount of suljphur (in pyrites), giving 
rise to a disagreeable odour during combustion. 
d. Occasional presence of lime, which gives the quality of 
fusibility. 
e. Tendency to fall to dust or “ small” on exposure or desiccation. 
i. Burn well only when associated with some more inflammable 
fuel, such as wood, peat, or Palseozoic coal. 
Nevertheless, in the absence, or with a mixture, of fuel of a superior 
kind, this class of coal is, or may he, used as a domestic fuel, 
3 D 
VOL. V. 
