280 TlMEHRI. 
position in which it was found, alike point to the same con- 
clusion. The existence ot gold in solution in the waters 
of our drifts being thus established, it is supposed that its 
deposition, or precipitation in metallic form, is strongly 
influenced by the passage of thermo-electric earth-cur- 
rents, probably generated by the unequal heating of the 
surface of the earth by the sun's rays in passing from 
East to West. As is to be expected in a tropical country, 
earth-currents are very pronounced on our gold-fields, 
and experiments I have made point to the same conclu* 
sion as that arrived at in Australia, namely, that '*' there 
is a remarkable relation between the conductivity of 
the adjacent rock country and the richness of an 
alluvial drift." As aids in prospecting several electrical 
appliances have been introduced, consisting mainly 
of modifications of the induction balance and the tele- 
phone and other more simple apparatus, but their practi- 
cal utility has not yet been generally recognised; still if 
the theory of earth currents be proved to be of general 
application it may open up a wide field for their useful 
employment. 
Although the discovery by SONSTADT of nearly a 
grain of gold to the ton in sea water is comparatively a 
recent occurrence, the fact of gold being brought up by 
the waters of terraneous springs appears to have been 
well-known in very early times. KTESIAS describing a 
fountain of this kind in India states that every year the 
gold was dragged up in a hundred earthen amphora at 
the bottom of which, when broken up, the gold was found 
hardened. In some of the Western States of America 
there exist thermal springs whose waters flowing out 
through fissures produced by subterranean forces are 
