6 LIQUID AIR. 



liquid air causes a film of vapor to form which momentarily prevents 

 actual contact and hence injury. It is but a moment, however, and 

 woe to him who leaves it in too long. On the same principle one may 

 touch with a moist finger a very hot flatiron, but woe if he touches too 

 long. 



The most delicate rose dipped in liquid air will not change its 

 color. But it is frozen so hard that its petals are brittle like gliiss and 

 if dropped will break in innumerable fragments. The same with a 

 head of lettuce and other vegetables. An egg becomes so hard that 

 the yolk is like dust or the pollen of flowers. Butter becomes so 

 brittle that it may be pounded into a fine powder in a mortar. Ice be- 

 comes milky and easily crumbles. 



Uses of Liquid Air. It is not likely that liquid air can ever 

 be used for power or for practical refrigeration; first, because its ex- 

 pansive power is not great enough it can't do more than to regain its 

 original state, i. e,, 1 foot to expand to 800 while water in the form 

 of steam expands from 1 to 1,700. Second, because of its extreme 

 cold, freezing everything with which it comes in contact. We can 

 hardly realize what 312 means. One of its greatest uses, how- 

 ever, is in surgery, and it is now used in all the great hospitals of the 

 world. 



For Operations. Patients who cannot take anaesthetics can 

 have the parts to be cut off, or cut out (like. e. g,, cancers), sprayed 

 with liquid air, which freezes them solid, when the surgeon can make a 

 perfectly painless operation, and also perfectly bloodless. When the 

 cutting has to be deep and where it formerly was impossible because 

 the flow of arterial blood could not be controlled, it is now easily done 

 by means of liquid air. 



Consumption Cured. It is known that air consists of about 

 78 or 79 per cent, of nitrogen, and 20 or 21 per cent, of oxygen, with 

 some carbonic acid gas and watery vapor. When liquid air evapor- 

 ates, the nitrogen, being much more volatile, passes off first, so that 

 after liquid air has been exposed for a time, the liquid remaining is 

 very rich in oxygen. This rich liquid can be preserved much longer 

 than the original, and can be used to enrich the air taken into the 

 lungs of a consumptive patient. In fact, in the earlier stages of the 

 disease, this is said to be an unfailing remedy and will, in a compar- 

 atively short period, effect a perfect cure. 



Yellow Fever. Low temperature is the only thing known that 

 will kill or render ineffective the germ of yellow fever. If a patient 

 can be kept wrapped in ice, he usually recovers. But it is now 

 claimed that if he is wrapped in blankets through which a can ot 

 liquid air is made to evaporate slowly, speedy recovery is almost abso- 

 lutely certain, while the suffering and distress is immediately relieved. 



Dyspepsia Cured. A Russian physician, experimenting with 

 liquid air, placed a dog in a small room where the temperature was 



