246 THE BOTTOM OF THE SEA. 



this gas had been compressed. The man Cf^rried this 

 reservoir on his back, and it communicated with his 

 mouth by a tube. 



Mhurr also made attempts to improve the appa- 

 ratus in France, but without superseding the original 

 invention. In England some form of the apparatus 

 was constantly used, and, in 1830, the discovery of 

 caoutchouc gave a great impulse to this industry, 

 and improvements became more feasible, at the same 

 time that they were more necessary than ever. This 

 was the state of affairs when two Frenchmen — M. 

 Rouquayrol, a mining engineer, and M. Denayrouze, 

 a naval lieutenant — solved this difficult problem. 

 Their apparatus suffices for all the exigencies of sub- 

 aqueous work. Whether the man be naked, or covered 

 with impervious clothing, his respiration depends 

 entirely on the exercise of his own will, anu on the 

 power of his lungs. 



This result is obtained by means of an artificial 

 lung or supply-regulator, which consists of a reservoir 

 made of steel or iron, capable of resisting very great 

 pressure, and surmounted by a chamber so constructed 

 as to regulate the afflux of air. The diver carries 

 this apparatus on his back. A respiratory tube issues 

 from this chamber, and is terminated by a moutl\- 

 piece composed of a piece of sheet-caoutchouc, which 

 is lield betw6>en the lips and the teeth of the diver. 



