THE UNDERGROUND WATERS OF NORTH-WEST YORKSHIRE. 7 
It is worthy of record that some forty to fifty years ago 
or more, when ore was washed in the mines about Pike Daw, 
the stream issuing from the Cove was discoloured. The writer 
has often been told this by villagers who had seen it. 
In 1879 Mr. Walter Morrison, the late Mr. Thomas Tate, 
of Leeds, and other members of the Yorkshire Geological and 
Polytechnic Society,"^ made certain experiments with the result 
that they concluded that Malham Cove and the springs at Aire 
Head were both connected with the Malham Tarn water-sinks. 
They further concluded that the Smelt Mill water-sinks in the 
Streets on Malham Moor were not connected with Malham Cove, 
and the outlet was not discovered. 
The nature of these experiments may be more fully described. 
Chaff was tried at the Smelt Mill, and both chaff and bran at 
the Tarn water-sinks, but, although nets were set in the outlet 
streams, none was found to emerge. This is not to be wondered 
at, as a preliminary trial of bran had shown that it became 
waterlogged in the stream within forty yards. An attempt was 
made also at the Smelt Mill to stain the stream by introducing 
an aniline dye (magenta), but in a preliminary trial up-stream 
all colour traces disappeared in a distance of seven or eight 
yards. These several insertions, therefore, produced only negative 
results. 
The principal experiments were in flushing the streams by 
means of the sluice at Tarn Foot. 
The stream flushed at 4 p.m. united all the sinks at 4.25, 
and ten minutes later it began to over-flow the sinks and to 
follow the old stream bed towards Comb Scar. A few minutes 
after 5 p.m. this overflow was 150 yards long. 
"At 5.25, one hour and twenty-five minutes after leaving 
the Tarn, the water began to creep over the half submerged 
* Proceedings of the Yorkshire Geological and Polytechnic Society, 
N.S., Vol VIL, p. 177 (1879). 
