10 
THE UNDERGROUND WATERS OF NORTH-WEST YORKSHIRE. 
discharged the floods affect both Aire Head and Malham Cove ; 
but the latter, although a mile and a quarter nearer, lialf an 
hour after the former. He says that the passage to Aire Head 
may be along a vertical fissure, and that to the Cove for part 
of its course along a wide, shallow, and almost horizontal fissure. 
If so, the increased friction in the passage to the Cove may 
explain the retardation of the water. Professor Miall further 
says that measurement of the issuing streams shows that the 
Cove discharges more than half of the water which issues from 
the Tarn. 
Durins: the summer of 1899 the Yorkshire Geoloijical and 
Polytechnic Society took the matter up again at the instance of 
Mr. George Bray, of Leeds, who generously undertook to provide 
material for the experiments. This came about in a somewhat 
remarkable manner. 
At Easter, in 1899, these several experiments were the 
subject of discussion at the Cove by a party on a walking tour 
including the writer and Mr. F. Swann, B.Sc, of Ilkley. Mr. 
Swann suggested that the employment of some harmless medium 
such as common salt, which could be readily detected by simple 
chemical tests, and would be more likely to meet with success. 
By a happy and curious coincidence this party, three days later, 
met four strangers at Clapham who were discussing the under- 
ground waters of Gaping Gill Hole and Ingleborough. The 
conversation became general upon the subject of the underground 
waters of North West Yorkshire, and one of the strangers 
remarked that if any reputable and capable Yorkshire Society 
would take the matter up he would be glad to provide material 
for the experiments. 
One of the walking party, happening to be a member of 
the Council of the Yorkshire Geological and Polytechnic Society, 
said that if the gentleman were in earnest he would be 
glad to have his name and address. These were promptly 
forthcoming, and out of this chance meeting came the present 
investigations. 
