401 
ON THE CIRCULATION OF SALT AND ITS BEARING ON 
GEOLOGICAL PROBLEMS, MORE PARTICULARLY THAT OF THE GEOLOGICAL 
AGE OF THE EARTH. 
BY VVILLLVM ACKROYD, F.LC, F.C.S., PUBLIC ANALYST FOR HALIFAX. 
{Read Ajwil 25^/i, 1901.) 
Introduction- 
Common Salt or Sodium Chloride is probably the most widely 
distributed of all sodium compounds, as it is one of the most soluble. 
During our investigation of the underground waters of N.W. York- 
shire, a fruitful aspect of its solubility was presented to us in the 
disappearance of three tons of salt in a runnel of 19,800 gallons per 
day. It went down the Smelt Mill Water Sink and reappeared after 
10 days at Malham Cove, where the amount of combined chlorine 
in the water suddenly rose from one up to six parts per 100,000, 
aiid in the course of another eight days slowly fell to the normal 
unit.* We had a similar experience at Clapham. It is apparent, 
therefore, that any salt in the soil, or in underground channels is 
carried quickly away by the water, and such soil or underground 
channels would be thenceforth free from the compound, unless in 
the course of disintegration fresh quantities were exposed for solution. 
This, however, is so slow a process that it quite fails to account for the 
enormous amounts of chloride annually conveyed by rivers to the sea. 
The position is, perhaps, better seen in the following statement 
of fact : — The Widdop Reservoir, belonging to the Halifax Corpora- 
tion, contains some 640*5 millions of gallons of water, and I estimate 
it to contain 55 tons of salt. The 2,000 odd acres of gathering 
ground is moorland on Millstone Grit for the most part with a little 
of the Yoredale Hocks. Needless to say it is a saltless area, yet the 
55 tons of salt is renewed probably more than once a year in the 
course of filling up to replace the Corporate demands on the reservoir. 
The chlorides come down in the rain-water. We may take it then, 
as a working hypothesis, that rain has brought down the salt which 
has been derived from the sea, and that to the sea it quickly returns. 
*Proc. Yorks. (^eol. and Polytec. Soc, Vol. XIV. Pt. I., p. 17. 
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