497 
secretary's report, 1901. 
The Meetings and Field Excursions during the year have fully 
maintained their scientific value and interest, and the condition 
of the Society is thoroughly satisfactory. 
A Special Meeting was held under the presidency of Dr. Forsyth 
at the Church Institute, Leeds, on the evening of April 25th, for 
the purpose of hearing a paper by Mr. Wm. Ackroyd, F.I.C., on 
" Salt Circulation and its Bearing on Geological Problems." Mr. 
Ackroyd pointed out that salt was very widely distributed over 
the land by means of the rainfall. The Widdop Reservoir, for in- 
stance, which held some 640 million gallons of water, contained 
practically 55 tons of salt, which was probably renewed more than 
once in the course of the year, the salt coming down in the rainfall 
at the rate of about 172 lb. per acre per year. This salt was taken 
into the atmosphere from the sea, was carried over the land by the 
wind, and, falling with the rain, was borne back to the sea by the 
rivers. A distinction, he said, was to be drawn between cyclic sea 
salt and salt derived freshly from the earth, the amount of the latter 
being exceedingly small, a fact to be considered in criticising Pro- 
fessor Joly's calculation as to the age of the earth, which, briefly 
stated, was that the total of the salts in the sea, divided by the total 
borne down by the rivers, equalled the age of the earth. According 
to Professor Joly's calculation, that represented a period of ninety 
million years, but the rate of denudation was so slow that fully eight 
thousand million years would be required for the process, which, 
said the lecturer, was too long even for the most exacting biologist. 
Incidentally, Mr. Ackroyd referred to the saltiness of the Dead and 
Caspian Seas, which he attributed chiefly to cyclic sea salt, and only 
in a small degree to denuded earth salt ; and, in conclusion, pointed 
out that in the solvent denudation method of arriving at the age 
of the earth too little allowance had been made for the mass of salt 
carried by the rivers which had been derived from the ocean by 
atmospheric transportation, and consequently too high a figure 
had been adopted for the variable proportion of salt derived from 
the earth. 
