T)efcrlplion of a nc'V D'l-vwg Machine* 6$ 



from what follows, that this will be impoffible. The air 

 which furrounds the diver in this machine amounts to 

 fomewhat more than a cubic foot. Now if he inhales air 

 through the pipe fcrewed to the machine, his body mud 

 diftend a fpace equal to the volume of air inhaled, confe- 

 quently he comprefles fo much the air that furrounds him 

 in the machine. But as this is impoffible, on account of 

 its too great refiftance, he does not obtain air fufficient to 

 fupport life, and is almoft in the fame ftate as if furrounded 

 by water. To be convinced of the truth of this, let anyone 

 take a caflc, equal in content to one or two cubic feet ; prefs 

 his mouth againft the aperture of it, and try whether he can 

 without difficulty breathe back into it the air he has inhaled. 

 A larger fpace around the diver in the machine would make 

 breathing eafier, but would not render him fufficiently eafy 

 to labour. The interior air in the machine, therefore, muft 

 be connected with the pipe deftined for breathing, in order 

 that it may be at freedom to dilate as his body is extended; 

 and it is only by a conftruction of this kind, as (hewn at z 

 in defcribing fig. 5, that a man can breathe while inclofed 

 in fo fmall a fpace. The author, at firft, had furnifhed his 

 mouth-piece with a valve, that the air might be again ex- 

 haled through it; but this valve was fo ill conftrucled that it 

 conveyed the exhaled air into the pipe deftined for breath- 

 ing. As he found that this was attended with inconvenience, 

 on account of the moifture which adhered to it, he after- 

 wards omitted the valve entirely. 



The diver, therefore, muft fuffer the air inhaled through 

 the mouth-piece u to efcape through his noftrik into the 

 machine; and then the air in it will remain equally elaftic. 

 The next time he draws breath, the air in the machine will 

 be forced out from it at z by the diftention of his body. By 

 thefe means he will be able to breathe freely and eafily for a 

 long time ; and thus the chief difficulty is overcome. 



We cannot better conclude our account of M. Klingert's 



Vol. III. F diving 



