LIQUID AIB. 9 



gradually reduced to 100 below zero. After ten hours the dog was 

 taken out alive, but ravenously hungry. Then the doctor, who suffered 

 horribly from dyspepsia, tried it on himself. After ten hours' confine- 

 ment in the still, dry, cold of evaporating liquid air, he found himself 

 wonderfully stimulated. Continuing the experiments, the results were 

 truly marvelous. Both man and dog grew fat and developed not only 

 splendid appetites, but were able to digest their meals without the 

 slightest discomfort. 



Other Uses. Liquid air may also be used successfully in deep 

 sea diving; or for aerial navigation; submarine navigation; as a freez- 

 ing mixture around shafts or tunnels or when digging through quick- 

 sand; or in blasting; for making vacuum bulbs like the incandescent 

 electric lamp, and for scientific experiments and investigation. It may 

 possibly become extremely useful as an aid in burning poor, cheap fuels. 

 But to these and kindred objects its use is limited, and to invest money 

 in liquid-air-making companies would be a dangerous experiment, if 

 one expected any financial returns. 



WONDERS OF LIQUID AIR. 



The experiments made with liquid air are so marvelous that it is 

 not to be wondered at, that those who have not witnessed the experi- 

 ments refuse to believe them. Possibly the most striking experiment 

 is this: A quantity of liquid air is poured into an ordinary tea kettle 

 and the kettle is set over a hot fire of coals. The liquid air boils and 

 shoots in streams from the spout of the kettle, three or four feet high. 

 If, then, a glass of water is poured into the kettle the water will be 

 frozen in a few moments and the pieces of ice appear boiling about in 

 the liquid. If, however, the kettle is lifted off the burning coals its 

 under surface is found to be covered with frozen carbonic acid from 

 the fire and moisture from the room. Within an inch or so of the 

 burning coals ice had formed on the bottom (outside) of the kettle. 

 It is so marvelous that one can scarce believe his eyesight. Yet it is 

 true, as can be testified by many who have seen it. 



Another pretty experiment is shown in Fig. 7, where a rubber 

 ball is shown floating in a tumbler of liquid air. The vapor from the 

 liquid air flows over the edge of the glass not rising like steam, but is 

 easily mistaken for steam. The chill which the hand receives, how- 

 ever, if exposed to it, quickly convinces one to the contrary. When 

 the rubber ball has been in long enough to get as cold as the liquid 

 and is then taken out, it will be found as brittle as glass, and if thrown 

 against the wall, will shatter like a thin glass tumbler. 



Fig. 3 shows an ordinary tin pan or dipper, which had been im- 

 mersed for a short time in liquid air. When struck against a table or 

 any hard surface it is shattered like glass, as may be seen. Copper, 

 on the contrary, is not affected by it. Fig. 6 shows a sponge saturated 

 with liquid air, after most of the nitrogen has evaporated. When 



