572 TSC GLAMIB TIME, 
of acid or base. Under the old method of interpretation the sea 
salts, according to Dittmar, consist of — 
Percentage Total Tons 
Sodium chloride’ - - - 77.758 35,09 Onxel Our 
Magnesium chloride - - - 10.878 FLOgdu xan Ome 
Magnesium sulphate - - 4.737 22 exehOue 
Calcium sulphate - - - 3.600 1, 6001x) lO 
Potassium sulphate - . © 2 2.465 TAR 3 Or? 
Calcium carbonate - - > Opeyills TOOrx: TOs 
Magnesium bromide - - O:217, LOONXa1 One 
100.000 460,283 Xx) LOW 4 
A rude average of the composition of land waters and of the 
amounts of salts carried to sea annually, founded on the esti- 
mates of T. Mellard Reade, is here given for comparison. 
Approx. percentage ‘Tons annually 
Calcium carbonate : = - =) 50 27 OORXaTOS 
Calcium sulphate - = = = 20 1,080 x 108 
Magnesium carbonate - - - ae) days 216 x TOe 
Magnesium sulphate - - - 4 DUS) 5: 1K)? 
Sodium chloride - : = = Sel 216 x 10° 
Potassium and sodium, 2 : 6 Roe 
Sulphates and carbonates 
Silica - - - - = = EMA B78) Xx1Oe 
Other substances - - - - 5 270) XeLOl 
100 5,400 x 108 
These tables do not embrace the second equivalent of carbonic acid. 
From these data it appears that it would require only a little 
over eight and one half million years for the land waters to 
bring in a gross amount of salt equal to that of the ocean, but it 
would require very different periods to bring in the individual 
constituents. It would take 166 million years to bring down 
the sodium chloride, but fonly about 1.5 million years to bring 
down the calcium sulphate, and only about 60,000 years to 
bring down the calcium carbonate. It appears therefore that 
there must be agencies constantly removing the calcium carbon- 
ate and the calcium sulphate at relatively high rates. These 
particular figures are subject to all the uncertainties involved in 
