ACKROYD : ON THE CIRCULATION' OF SALT. 
409 
equals tlie geological age of the Earth. There can be no mathe- 
matical precision in any method for getting at the age of the Earth, 
and this latest method of attacking the problem appears no more 
precise than the rest. 
If we take the numerator, for the present, to be approximately 
correct, the degree of accuracy attainable will depend upon the re- 
liability of the denominator, and to this question my attention will 
be solely directed. 
It is assumed, in the first place, that the solvent denudation 
which yields the annual load of combined sodium to the seas has 
been uniform in its action from the first. Now, as a chemist, I have 
tried to picture to myself the condition of things immediately before 
and after the consistentior status," when the cooling globe allowed 
of the condensation of aqueous vapour to form the first ocean. 
Oxides of the alkalies and alkaline earths, silicated and other- 
wise, would exist among the first compounds. Hydrochloric acid 
would admittedly be another, and as the temperature gradually 
lowered their incompatibility would result in the production of 
silica, aqueous vapour, and salts like sodium chloride. 
There is no more remarkable fact than the thoroughness with 
which hot water takes up chlorides from a hot surface with which 
it is in contact or prevents their deposition. I need only instance 
the formation of boiler scale. The boiler water increases the amount 
of its chlorides in solution so regularly with the amount of evaporation 
that it has been made the basis of a technical method, now often 
used for finding the evaporative power of coal. The boiler scale 
contains only the minutest trace of chlorides. 
I imagine then that the seething Archsean Sea would dissolve 
all soluble chlorides from the ocean floor and rocks of those times, 
and as the deliquescent salts appeared on new land surface they 
would be washed away by every shower, so that to all intents 
and purposes the sea was salt from the first." My ideas here 
run somewhat parallel to those of Professor W. J. Sollas, who, in 
his able address to the Geological Section of the B.A. at Bradford, 
observes : '' The ocean when first formed would consist of highly- 
heated water, and this, as is well known, is an energetic chemical 
