90 
The learned authors of the article on "Ocean and Oceanography’^ 
in the Encyclopedia Rritannica, who quote Roth's figures, also 
remark; "The salts of salt lakes which have been formed in the 
areas of internal drainage in the hearts of the continents by the 
evaporation of river water are entirely different in composition 
from those of the sea, as the existence of the numerous natron and 
bitter lakes shows." The water of Lake Van. for example, con- 
tains 5.397G grams of sodium carbonate per 1000 grams of water, 
to 8.0500 grams of sodium chloride. The principal soluble salts 
formed by the chemical action of the weather on the compound 
silicates which form the bulk of the crystalline rocks are carbon- 
ates or bicarbonates of the alkalies and alkaline earths, and as 
a natural consequence these salts must be expected to predominate 
in the surface waters leaching through masses of weathering rock. 
Unless chlorine be present as a constituent of the rocks, no con- 
siderable amount of sodium chloride can be formed from such 
weathering, and unless, therefore, our crystalline rocks can be 
shown to carry a quite perceptible amount of chlorine in them on 
the average, there is no reason to look to them as the source of 
the salt so plentiful in the ground w^ter. So far as chemical 
analyses have been published chlorine has very rarely been noted as 
a constituent of our crystalline rocks at all, and the petrological 
descriptions do not indicate any unusual abundance of chlorine- 
bearing minerals. 
In this connection it may be of interest to refer to the tables 
of analyses of natural waters in Australia given in the Report of 
Proceedings of the Interstate Conference on Artesian Waters, 
1912. Appendix B. gives 54 analyses of bore waters in New South 
Wales, characterised by the carbonates of sodium, potassium, cal- 
cium, and magnesium being in almost all cases greatly in excess of 
the sodium chloride present. In Appendix PI. there are several 
hundred analyses of New South Wales artesian and subartesian 
waters, and the great majority of these also show alkaline carbon- 
ates in large excess over sodium chloride, although a few are 
mainly saline waters. In Appendix M., Tables 11 and 111 give 
65 analyses of waters from Western Australia, but in these sodium 
chloride is almost always in large excess over all other salts pre- 
sent, and carbonates are of quite subordinate importance. The 
reversal of the relative proportions of chlorides and carl)onates in 
the ground water at once suggests some essential difference 
between the conditions of the two provinces of New South Wales 
and Western Australia. Appendix T. shows 48 analyses of bore 
and well waters from the Mallee country of Victoria, with a great 
preponderance of sodium chloride over all other constituents. In 
Appendix Y. there are 34 analyses from South Australia, of waters 
from the Great Australian Basin ; in 28 of these sodium chloride is 
the most abundant salt present, hut iu 6 cases sodium carbonate 
predominates, and in 11 the sodium carbonate is next to sodium 
