330 Transactions. — Geology. 



How long may such quantity of coal be reasonably expected 

 to last ? 



If we turn to the records of our output since 1878, we shall 

 find that the total quantity of coal raised in the colony in that 

 year was 162,218 tons, and in 1881 337,262 tons, which is 

 equal to an increase of 100 per cent, in three years. During 

 the last seven years the growth of the output has been slower, 

 and shows something of a geometrical or proportional rate of 

 increase. 



The latest and highest recorded output — that of 1887, 

 amounting to 558,620 tons — bears but a small proj)ortion to 

 our vast stores of coal, which in fact contain the former 2,181 

 times. But a little consideration will show that it would be 

 absurd to speak as if we had enough coal to last for more than 

 two thousand years, since the present rate of consumption is 

 not a fixed but a growing rate. 



The production of coal in Great Britain in 1887, according 

 to the reports of the Inspectors of Mines, was 162,119,812 

 tons, which is contained in the total estimated available quan- 

 tity of coal — amounting to 146,480,285,398 tons, as determined 

 by the Eoyal Coal Commission in 1866 — no less than 903 

 times. With this material it has been estimated by various 

 authorities that the coal of Great Britain must be exhausted 

 at periods ranging from eighty to one hundred and fifty years 

 from the ]3resent time. 



In New Zealand the coal industry is still in its infancy, 

 and it is in consequence impossible at the present stage of our 

 output to determine whether the rate of our increase is geome- 

 trical or arithmetical. 



It is obvious that the output is governed by two causes — 

 first, the natural increase of our population, and, second, the 

 growth of capital applied to the development and extension 

 of our manufactures. 



Starting from the actual output in 1887, the output at in- 

 tervals of ten years up to 1957 would be as follows — assuming 

 that the increase of output continues uniform with the average 

 yearly increase for the last seven years, which is sufficiently 

 near for our purpose : — 



1887 (actual output) 



1897 (calculated output) 



1007 



1917 



1927 



1937 



1947 



1957 



Tons. 



658,020 



910,000 



1,471,500 



2,397,000 



3,905,000 



0,503,000 



10,593,000 



17,250,000 



On the assumption that the facts of the past seven years 

 supply adequate indications of the law of consumption of the 



