14 THE UNDERGROUND WATERS OF NORTH-WEST YORKSHIRE. 
On the 27th, the Sub-Committee visited the Water Sinks 
below the Tarn, and the Smelt Mill Water Sink. 
The samples collected gave the following figures on subse- 
quent analysis : — 
Chlorine. 
Parts per 100,000. 
Smelt Mill Stream M 
Malham Tarn, outlet ... ... ... 1-0 
Malham Cove 0-95 
Aire Head 1-0 
, Average ... ... 1*01 
One part of chlorine represents 1-647 parts of common salt. 
As a trial experiment a solution of 4 oz. of fluorescein 
was put in the Water Sink below the Tarn outlet at 3.15 p.m. 
and observers were stationed at the Cove and at Aire Head for 
several hours after. No evidence of the presence of fluorescein 
was obtained at either of these outlets up to the evening of 
the 27th of May. 
At a meeting of the Chemical Tests Sub-Committee, held in 
Leeds on June 9th, present Messrs. F. W. Branson, G. Bray, and 
B. A. Burrell, it was decided to use salt at the Smelt Mill Water 
Sink, ammonium sulphate at the Tarn Water Sinks, and fluor- 
escein dissolved in 10 % aqueous potassium carbonate at Tranlands 
Beck, these chemicals being all discernible in minute proportions 
in the presence of each other, and being also comparatively 
innocuous to fish or cattle. 
To the second Committee Meeting, held at Malham, a general 
invitation to members of the Society was issued to proceed with 
the work under the guidance of Messrs. Wm. Ackroyd, F.I.C, 
and F. W. Branson, F.I.C. The members met on June 21st at 
the Buck Hotel, and after dinner a meeting was held, at which 
the next day's work was planned, Mr. Walter Morrison, M.P., 
occupying the chair. There were present : — Messrs. W. Ackroyd, 
G. Bingley, F. W. Branson, G. Bray, B. A. Burrell, F.I.C, S. W. 
Cuttriss, C. W. Fennell, Rev. J. Hawell, B. M. Kerr, W. Stewart, 
