llXiO] on Means of Saving Life in Coal Mines. 48o 



his oxygen is automatically economised, and hence he could last out 

 longer if need arose. 



The breath expelled from the mouth goes into a receptacle con- 



[Photograph.] 



taining the caustic soda or potash, which absorbs the carbonic acid. 

 The breath is then refreshed by a fresh addition of oxygen from the 

 cylinder, then it goes to a radiator to cool it, and, thus renovated, it 

 is again sucked into the lungs. The nitrogen of the air goes round 

 and round, being breathed and exhaled over and over again, the 

 oxygen is turned by the body into car])onic acid and in this condition 

 is absorbed by the potash. 



Stations are being established all over the country at which men 

 are to be trained to the use of this apparatus. It can hardly be said 

 to be perfect even yet, and a good many men have perished through 

 accidents Avith its use. There is, however, no doubt that these 

 difficulties will be overcome. 



The photographs show the Fleuss apparatus, and the Shamrock 

 apparatus designed by W. Mayer, of Westphalia, and the Draeger 

 apparatus, another form of the Shamrock. The " Weg," or Mr. 

 W. E. Garforth's, apparatus is also shown. 



[Four photographs.] 



In addition to these, two other apparatus must be mentioned. 

 The Aerolith consists of a sack containing liquid air absorbed in 

 loosely packed asbestos. There is no need for any potash, for the 

 air expelled from the lungs is simply breathed away. The full charge 

 of the bag is 5 litres of liquid air. As it escapes it becomes expanded 

 and cooled. It is pleasant to use and the apparatus is very light, as 

 there are no heavy cylinders to carry. This is one of the latest 

 applications in a practical way of the work done by Sir James Dewar. 

 The next apparatus I have great hopes of. It consists of a bag 

 containing sodium-potassium-peroxide. This extraordinary chemical 

 seems as though expressly designed for breathing apparatus, for 

 when damped it exhales oxygen, leaving caustic soda and potash 

 behind, which in their turn absorb carl:»onic acid. 



It would be perfect, were it not that the chemical is very inflam- 

 mable, and two men, one in Germany and one in London, have been 

 injm'ed by its use. 



Dr. Hill's interesting experiments iu giving oxygen to exhausted 

 athletes have recently attracted considerable attention. 



I have here an apparatus, designed by Dr. Leonard Hill, for 

 supplying oxygen to invalids by means of sodium-potassium-peroxide. 

 In glass bottles it is quite safe. 



[Siebe Gorman oxygen apparatus and powder.] 



