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existence upon the earth man only benefited by those elements 
which were widely and more or less evenly distributed throughout 
the earth’s immediate surface, or was led by blind chance to con- 
centrations of those others which his growing knowledge led him 
to look upon as indispensable. As time went on an exhaustion of 
some of the widely distributed elements was already apparent, 
the local exhaustion of phosphorus in the soil for instance, and 
man became more than ever dependent upon natural concentra- 
tions and upon his purely chance discovery of them. First to his 
aid came a glimmering of the relationship between ore deposits 
and phy si ©graphical and geostmetural features. Last, and to an 
imperfect extent, geochemical principles are being, and must con- 
tinue to be, developed to guide him in his search. Some few broad 
geochemical ideas arc of common knowledge, and often uncon- 
sciously applied. Such for example as that chromite (chrome ore) 
is invariably associated with rocks of a definite chemical type, 
viz., the so-called ultra-basic rooks : that galena and silver minerals 
are almost always found together in genetic relationship : that 
pyrites and gold are not uncommonly co-precipitated in nature : 
that commercial felspar is never found anywhere but in the pro- 
ducts of consolidation of acid, i.e . , persilicic magmas. A few such 
truths are widely known and freely made use of in practical mining, 
but little appreciation is yet shown of the fact that other similar 
genetic relations of a chemical nature are fairly well established 
and many others must be awaiting discovery, with equal possi- 
bilities of practical application in the two branches of mining, viz., 
prospecting, or the detection of new masses of ore, and exploit- 
ation, or the following up and bringing to the surface of the whole 
valuable portion of a known mass. 
Your attention lias already been drawn to the fact that in 
Western Australia mining has reached a stage of serious decline, 
which has already reacted deleteriously upon the whole community 
and can only be remedied in one of two ways, viz., by the early 
discovery of new mineral deposits equally profitable to those which 
have been worked in the past, or by the reduction of the cost of 
working those known deposits to such an extent as to widen con- 
siderably the limits of payable ore. Science can render aid in 
both directions. 
Sir William Crooks, in his Presidential Address to the British 
Association in 1808, was the first to sound the ominous note of 
Famine in regard to mineral supplies necessary for our existence. 
In this notable address lie pointed out the absolute dependence of 
man on a sufficiency of nitrogenous food, and the impossibility of 
producing this without an unfailing and indeed increasing supply 
of soluble nitrates or ammonia salts. At the same time statistics 
proved that our then known natural sources of both, viz., the mineral 
nitrates of Chili and India, and the coals of known and strictly 
