36 THE UXDERGROUND WATERS OF NORTH-WEST YORKSHIRE. 
Mr. Tate said "It is impossible to believe that water 
flowing undiluted through a mile and three-quarters of limestone 
strata should, during its voyage, lose between two and three 
degrees of hardness." 
The fact appears to be that, as Mr. Tate said, the Smelt 
Mill Sike contributes only about o^yth of the water issuing from 
the Cove, the remaining ^-|jths consisting of the rainfall absorbed 
on the two square miles or more of country to tlie westward 
of the Watlowes, and of the water which sinks in the potholes 
on Outside, and that this water is somewhat less hard than 
that from the Smelt Mill. But any argument drawn from so 
slight a difference of hardness must be inconclusive. 
V. COXCLUSIOXS AND REMARKS OF THE UnITED SuB-CoMMITTEES. 
A. — Malham Cove Spring. 
That this discharges : — 
1. The water from Smelt Mill Sike. 
2. The surface water from the limestone area west of the 
Cove and the Dry Valley. 
3. Under certain conditions a portion of the Tarn water. 
jSTote. — It is not quite certain, however, that these con- 
ditions have not to be artificial or exceptional. Flushes 
from the Tarn sometimes affect the Cove, but if the Smelt 
Mill Sink could be similarly flushed at the same time all 
the Tarn water might pass on to Aire Head. As a general 
rule it probably does so, unless there happens to be a marked 
difference in the rainfall between the Tarn and Smelt Mill 
gathering areas which renders the Tarn supply abnormal 
relatively to that of the Smelt Mill side. 
It is only the Tarn stream which can be experimented 
upon by flushing, so that it is possible that if the Smelt 
Mill side, whether artJficially or by rainfall, were flushed to 
a o-reater desrree than the Tarn stream some Smelt Mill 
water might come out at Aire Head. It seems probable that 
• an underground watershed exists between the route taken 
by the Tarn Sinks to Aire Head water and Malham Cove. 
