THE UNDERGROUND WATERS OF NORTH-WEST YORKSHIRE. 11 
The Council of the Yorkshire Geological and Polytechnic 
Society accepted this generous offer on the part of Mr. Bray 
(who has taken a personal and active interest in the inquiry), 
and appointed a large and representative Committee to conduct 
the investigations. 
Further points of interest and inquiry may be stated, such 
as : Why does the Tarn water flush Malham Cove sometimes 
and not always ? Why does the Tarn water reach Aire Head 
before Malham Cove, which is a mile and a quarter nearer ? 
Why were the chemicals introduced so long in transit ? Are 
there underground caverns between the sinks and the outlets ? 
II. Engineering Report. 
BY C. W. FENNELL, F.G.S., AND J. A. BEAN, C.E. 
In reference to the jjauofins: of the flow of water at the 
o o O 
streams near Malham Tarn, on the 22nd June, 1899, we have 
carefully considered the information then obtained, and have to 
report as follows : — 
On the 17th June we visited Malham, and after very con- 
siderable difficulty, owing to the rocky bed of the streams, we 
were able to select three positions for the gauges marked 1, 2, 
and 3 on the annexed sketch plan, (Plate XII.). 
Xo. 1 gauge on the outlet of the Malham Tarn sluice. 
Xo. 2 on Malham Beck, above Malham village. 
Xo. 3 on the stream from Aire Head. 
We were thus enabled to gauge the volume of water going 
down the Malham Tarn Sinks, and the increase in volume, if 
any, at the Cove and at Aire Head. We also gauged the water 
at the Smelt Mill Sink, the flow being constant at the rate of 
19,800 gallons per day. The gaugings at the outlets, viz., the 
Cove and Aire Head, were taken ever}' 15 minutes from 7 a.m. 
until 5.45 p.m., and the observations are carefully plotted on the 
diagram accompanying this report (Plate I.). The results of the 
three gauges may be readily seen on reference to this diagram. 
