W. Achroyd — The Circulation of Salt. 445 



III. — On the Cieodlation of Salt in its Relations to Geology. 

 By William Ackeoyd, F.I.C, F.C.S., Public Analyst for Halifax. 



A SEA-BREEZE is salt-laden in varying degree. On a fine 

 dry day it may contain as much as 22 milligrams of salt 

 per cubic metre of air (Armand Gautier, Bull. Soc. Chim., 1899 

 [iii], 21, 391-392). This invisible salt is washed out of the 

 atmosphere by rains, and finds its way back to the sea. 



Salt circulation is more evident in times of storm, when the 

 amount carried on to the land from the sea may be enormous. 

 Thus, during the storm of January 6th and 7th, 1839, newspaper 

 records make it apparent that tons of salt per acre were spread over 

 Lancashire and Yorkshire, which had been brought by the gales 

 from the Irish Sea ; right away over the Pennine hills the trees 

 were white with salt. 



The phenomenon has been entirely ignored in our physiographic 

 literature, and credit is due to Professor Joly for having made an 

 allowance of 10 per cent, for such transported salt in his calculation 

 of the age of the Earth. 1 have attempted to give the subject of salt 

 circulation its due importance in a paper read before the Yorkshire 

 Geological and Polytechnic Society, which will duly appear with 

 Addenda in the Society's Proceedings. A preliminary report 

 appeared in the Chemical News for June 7th, 1901. In the course 

 of the paper I venture the opinion that 99 per cent, ought to be 

 allowed for cyclic sea-salt in employing soluble river contents as 

 a measure of time ; to this Professor Joly replied on June 28th, 

 and my rejoinder in the same journal will be found on August 2nd. 

 I am here concerned with his article in the August number of this 

 Magazine. 



On the Origin of the Saltness of Salt Zahes. — Many determinations 

 of chlorine in rain-water are on record, but a fulness of information 

 is decidedly wanting. The chlorine fluctuates widely, and the laws 

 determining the variations have yet to be experimentally worked 

 out. A six months' study of one locality will be found in my paper 

 "On the Origin of Combined Chlorine " (Journ. Chem. Soc, 1901, 

 vol. Ixxix, pp. 673 and 674), where records of the fluctuations of 

 chlorine in the rain-gauge and reservoir of Widdop on the Lanc- 

 Yorks. border are given. It is necessary to say here, a point which 

 will again be referred to, that it is customary among chemists to make 

 chlorine a measure of sodium by calculating the chlorine in rainfall into 

 sodium chloride. Employing this convention, Bellucci calculates that 

 37-8 lbs. of common salt per acre is deposited every year at Perugia, 

 some 75 miles from the sea-coast, and I may add that I find in the 

 Pennine hills the deposit calculates out to 172 lbs. per acre per year. 

 Such facts, taken in conjunction with observations like Gautier's, 

 make it probable that wherever sea-winds reach to carry moisture 

 there the falling rains bring down chlorides, and the general disposition 

 of iso-chlors proves this. It is justifiable, then, to suppose that an 

 inland lake may owe much of its salt to this source. I have shown 

 by calculations that the Pennine reservoir already referred to with 



