538 PHILOSOPHICAL TRANSACTIONS. [aNNO 1774. 



that are put into the exhausted receiver of an air-pump, where the diminution of 

 pressure is many times greater than on the summit of the highest mountains, it 

 is probable it was an accidental disease, or was owing to some violent exertions in 

 ascending. And in the curious account Dr. Halley gives of his descending in a 

 diving bell so low, as to have the weight of many atmospheres over him, no 

 other complaint is recorded, but a disagreeable sensation, as he was descending, 

 like something bursting in his ears, and which recurred at about the same depth 

 of water in his ascent. 



From the above observations of Dr. Halley on the sensation in his ears, when 

 he descended and ascended in the diving bell. Dr. D. was led to imagine, that 

 the air contained behind the tympanum in the vestibulum cochlea, and semicir- 

 cular canals of the ear, had found or made itself a way into the Eustachian tubes, 

 or into the external ear, by some undiscovered passage; and concluded, that a 

 similar operation might be of service to some deaf people, where the immediate 

 cause of their deafness might be owing to the excess or defect of this internal 

 air. For this purpose a cupping glass, which had a syringe to exhaust it, was 

 put over the ears of three different people, who were very hard of hearing. The 

 inequality of the mammoid process of the temporal bone, made it necessary to 

 put 2 or 3 circles of wash leather dipped in oil around the helix of the ear. On 

 working the air-syringe, the external ear swelled, and became red; and at 

 length the patients complained of pain in the internal ear, and the air was read- 

 mitted. One of these 3 patients heard considerably better immediately after the 

 operation, and received permanent advantage; the others received neither benefit 

 nor disservice. If this small degree of success from the use of the cupping glass, 

 as so little pain or trouble attends the operation, should encourage other deaf 

 persons to make use of it, it may be a means to give some light into the intri- 

 cate diseases of this organ, the structure of the parts of which, and their uses 

 are yet so little understood. 



XXXVII. Jn Account of a Storm of Lightning observed March 1, 1774, near 

 fVahefield, in Yorkshire, by Mr. Nicholson, Teacher of Mathematics in IVake- 

 Jield. p. 350. 



On the 1st of March, about half past 6 in the evening, as I was returning 

 from Crofton, a village near Wakefield, I saw, says Mr. N., in the north-west, 

 a storm approaching; the wind, which had been strong all the day, setting from 

 the same quarter; and as in the afternoon of the same day, there had been some 

 violent showers of hail, I made the best of my way to the turnpike at Agbridge. 

 The air was so much darkened, before the storm began, that it was with diffi- 

 culty I found my way. When I was about 300 yard^ from the turnpike, the 

 storm began; when I was agreeably surprised with observing a flame of light. 



