LIQUID AIR. 



Ti iT ANY substances have three 



/y I forms — solid, liquid, and gas- 



X JL eous. It takes cold to change a 



gas to a liquid, and more cold 



to reduce the liquid to a solid. Steam, 



water, and ice are good examples. 



Air is a substance that requires so 

 much cold to reduce it even to a liquid 

 state that we know nothing of it as a 

 solid. Our Smithsonian Institution 

 gave Professor Dewar of the Royal In- 

 stitute of London a gold medal for his 

 discovery in regard to reducing it to a 

 liquid. 



No artificial cold is intense enough 

 to affect air except when it is confined 

 under great pressure. When a gas is 

 compressed and made cold it tends to 

 liquefy. But it takes enormous press- 

 ure and intense cold to make liquid air. 



It is a grayish substance that may be 

 carried about like water. It has a ten- 

 dency to steam up, and when its vapor 

 comes into contact with flesh a cooling 

 sensation is produced. But living flesh 

 cannot long remain in contact with 

 the liquid itself. It produces a wound 

 much like a burn. 



By careful use of liquid air in sur- 

 gery, the flesh may be so put to sleep 

 that the surgeon's knife is not felt by 

 the patient as he watches the cutting. 

 A cancer has been cut out b}' liquid 

 air in a sort of burning process that 

 needed no knife. Cremation has been 

 accomplished by its use. 



Cremation is burning. Burning is 

 the union of oxygen with the substance 

 consumed. Liquid air left exposed to 

 common air evaporates and sends out 

 its nitrogen so that almost pure liquid 

 oxygen is left in the vessel. This 

 placed in contact with the body to be 

 consumed soon sends all except its 

 mineral parts flying away in the 

 atmosphere in a vapor thinner than 

 smoke. 



It is the coldest substance known. 

 It takes an intense cold to produce it, 

 and it has to remain cold much as ice 



is cold, only very much more so, as 

 long as it is liquid air. For this reason 

 it is carried about in vessels con- 

 structed so as to exclude the heat. 

 Mercury dropped into it becomes a 

 solid block, and meat quickly freezes 

 so hard that it is brittle as. glass and 

 may be broken into a thousand pieces. 



The liquid oxygen left after expos- 

 ure of liquid air may be placed in a 

 hollow in a cake of ice. Dip into it a 

 watch spring and touch a lighted 

 match to it and you will see the steel 

 spring burn as if it were full of pitch. 



Eight hundred gallons of common 

 air are compressed into one gallon of 

 the liquid. The liquid is unattractive 

 and very common-looking. You would 

 not suspect its great powers by m»erely 

 looking at it in a dish. But when it 

 expands into common air it has tre- 

 mendous energy. A few drops con- 

 fined in a closed iron pipe will explode 

 and blow the metal to atoms. 



When first produced it was so ex- 

 pensive a product that its value was 

 above that of rubies. Now it is cheap 

 and becoming more so. We expect it 

 to become an ordinary article of com- 

 merce. One company is capitalized at 

 $10,000,000 to push its use in place of 

 steam and electricity. 



Probably some of the companies ad- 

 vertising shares to sell are putting its 

 powers far too high. One company's 

 agents are representing that a very 

 little of it in a cup will keep an icebox 

 cold all day, and that a pound of it 

 will reduce the heat in a large house 

 on a warm summer day so that it may 

 be kept cool at very small expense. 



These extravagant claims are prob- 

 ably made for the purpose of deceiving 

 people so they will 'buy shares. The 

 facts seem to show that a pint of liquid 

 air will not cool an ice box much more 

 than will a pound of ice. The effect 

 of a gallon of it in a large house would 

 scarcely be felt in July, except for a 

 short time in one or two rooms. 



