FAIRLEY : BLOWING WFLLS. 
415 
mean result of about 10 millions of cubic feet of space as that of 
the cavity affected by the barometric changes. 
Of course if there be any other unobserved openings into 
this cavity, the area of the enclosed space must be so much the 
larger in proportion to the amount of air passing by other ways. 
In February, 1 880, I took two of the largest dry meters in 
the possession of the Leeds Corporation, not in actual use at the 
time, coupled so that one registered the in, and the other the out- 
current It was found, however, that these meters were so greatly 
strained by the force and quantity of the current, that they were 
soon thrown out of gear from their incapacity to pass the quantity 
of air fast enough. The air also forced its way out under the flags 
covering the well. Indeed at first the meter passed about double 
the quantity of air which it was constructed to do to give an 
approximately accurate measurement. 
Mentioning my difficulty to Mr. Glover, of the firm of Messrs . 
Glover & Son, Dry Meter Manufacturers, of London, he kindly 
placed two large meters, constructed to pass 3000 cubic feet per 
hour at the maximum, and I had these coupled to the pipe from 
the shaft of the well as before, one to register the out, and the 
other the in-current. Mr. Hutton took frequent readings of the 
barometer and of the air registered by the meters. 
Table II is simply a tabulated copy of the results noted by 
Mr. Hutton according to my instructions. 
