TIUNSACTIONS OF SKCTION A. 545 



■of oxygen. Conceiving that tliere must he a large underground cavity com- 

 municating with the shaft of the well, T thought the phenomena worthy of 

 investigation, and through Mr. Ilutton's kindness and assistance 1 was able to 

 make these experiments. 



The out-currents were very powerful and attracted the attention of everyone in 

 the neighbourhood, and equally powerful in-currents were observed during the 

 periods of a rising barometer. On descending the shaft of the well 15 yards, the 

 fissures in the sandstone were observed where these currents passed. Analyses 

 were made of the sandstone and the water in the well. I then attempted, by 

 careful readings of the barometer at Solberge, and measurement of the currents, to 

 obtain, by the application of Boyle's law, the approximate volume of the cavity. 

 The readings of the instruments were made by Mr. Hutton. 



Experiments were made, first with a Biram's vane anemometer ; afterwards 

 with very large dry gas-meters. Only those observations could be used where the 

 barometric change continued so long that the current produced had time to 

 exhaust itself. The temperatures of the out-currents and of the air were also 

 noted. In cold weather the out-current was warmer than the outside air. 



The anemometer observations were made in July and in December 1879. Of 

 these, two sets of observations made in July, and two made in December, give an 

 average result of 10-.3 millions of cubic feet as the approximate volume of the 

 cavity. 



The dry gas-meter observations were made in March and April 1880, with 

 two meter.s kindly lent by Messrs. Glover & Son, of London, capable of passing 

 about 3,00.0 cubic feet per hour.' Even this capacity was insufficient, and 

 the experiments were stopped by the meters being thrown out of gear hj the force 

 and rapidity of the current. One set of observations were, however, tolerably 

 perfect and complete, and give a capacity of ten millions of cubic feet very nearly. 

 These volumes correspond to a cubic space of about 217 feet. 



Caverns are generally found in limestone rocks. Geologists consider that the 

 magnesian limestone would be here about 400 feet below the surface. The 

 nearest exposed section is, however, at some distance. 



Another blowing well is located at Langton Hall, 5 miles N.W. from Soll^erge, 

 both being located on the rising groimd separating the valleys of the rivers Wi,ske 

 ■and Swale. In this case also the currents consist of air, and their direction and 

 volume depend on the changes of the barometer. 



Of course the measurements mentioned above cannot give more than a minimum 

 Tolume for the cavity, if there are any other openings. 



The third blowing well I have not yet visited. It is situated on the estate of 

 Mr. Paver Crow at Ornhams, 2 miles south from Boroughbridge. I have analysed 

 the water, which is somewhat similar to that of the water at Solberge. The 

 •>current8 here are very powerful, causing a rushing noise in passing through the 

 ifissures. 



In all these cases the currents are extremely sensitive to the chajges of the 

 barometer. I have examined and inquired about other wells in the district, but 

 these are the only blowing weUs I have found. Other wells near Solberge, within 

 a mile of the blowing well, gave no currents. 



17. Some Bemarhs on Artificial Flight. 

 By Fred. W. Brearey, Hon. Secretary of the Aeronautical Society. 



- The author examined the various fallacies which have been entertained in 

 ancient and modern times with respect to the flight of birds, and explained some 

 of his own experiments during the last six years. With respect to the hollow 

 bones of birds, and the opinion of many that such an arrangement is intended as a 

 receptacle for a rarefied gas, he quoted a remark by the author of a paper read by 

 a member of the Aeronautical Society, that if the whole body of the bird were 

 filled with the lightest gas or even so much vacuous space, the supporting effect 



' They were coupled, so that one registered the ii>, the other the out-current 

 1881. N N 



