24 Furlher Experiments on the Combustion of 



if a shot was fired through their brain." This was evidently tfie" 

 rushing in of the air tiirough the Eusrachian tuhe. 



There arc now several diving-bells in use. Besides the one 

 at Howth, there is one at Holyhead, one at Ramsgate, and one 

 at Plymouth. They arc constructed under the superintendance of 

 Mr. Rennie, on Mr. Sineaton's plan, entirely of cast iron, in the 

 form of an ohlong chest open at bottom. — (Sec Dr. Brewster's 

 Encyclopedia, article Divitig Bell.) 



The one in whicii I descended is six feet long by four feet wide, 

 and six feet high, wiih twelve patent glass-lights, as used in ships' 

 decks, on the top. A descent in a diving-bell of this construc- 

 tion may be undertaken without any inconvenience, except the 

 above described sensation in the ears. I was for half an hour 

 under water more than twenty feet deep, and had light more 

 than enough to write and read. A constant supply of fresh air 

 is given by means of a forcing pump, and the respiration is not 

 in the least affected. The signals to the men, who manage the 

 bell al)ove the water, are given by means of striking with a ham- 

 mer once, twice or more times against the inside of the bell. 

 The number of strokes tells them in what direction you wish to 

 be moved. A diving-bell of the above dimensions may hold four 

 men. 



I wish much that some deaf person or persons, whose deafness 

 is owing to the cause above stated, might try the diving-bell ; and' 

 should they be benefited by it, hydraulic or other pressure en- 

 gines might be constructed to obtain the same end in houses or 

 hospitals. 



VII. Further Experiments on the Combustion of explosive Mix- 

 tures confined by JVirc-s,auze ; with some Observations on 

 Flame. By Sir II. Davy, LL.D. F.R.S. F.P.R.L* 



1. HAVE pursued my inquiries respecting the limits of the size 

 of the apertures and of the wire in the metallic gauze, which I 

 have applied to secure the coal miners from the explosions of 

 fire-damp. Gauze uuide of brass wire -'g- of an inch in thick- 

 ness, and containing only ten apertures to the inch, or 100 

 apertures in the sc[uare inch, employed in the usual way as a 

 guard of flame, did not communicate explosion in a mixture of 

 one part of coal gas and 12 parts of air, as long as it was cool ; 

 but as soon as the top became hot, an explosion took place. 



A quick lateral motion likewise enabled it to communicate 

 explosion. 



Gauze made of the same wire, containing 14 apertures to the 



* From the Pliilosophical Transactions for 1816, part i. 



iucli. 



