DIVISION FIRST, 



NEW DISCOVERIES. 



WONDERS OF LIQUID AIR. 



The most important discovery of tiie last years of the nineteenth 

 century was the discovery of the process of liquefying the atmosphere 

 we breathe, and that at a merely nominal cost. That the air could be 

 liquefied was known many generations ago, but the cost of securing 

 even a few drops was more than $1,000. As early as 1857 Prof. 

 Siemens, in Germany, first made a machine which it was thought might 

 make liquid air, but it was not a success. Prof. Linde, of Germany, 

 made the first successful machine in 1895. About the same time Prof. 

 Hainpson, in England, and Prof. Tripler, in America, were working on 

 similar machines, and without knowledge of Prof. Linde's apparatus, 

 perfected apparatus of their own which have since been improved 

 until now it is said that liquid air can be produced in a large plant at 

 a cost of 1 cent per gallon, and possibly at less. 



Liquid air is produced by compressing air until 800 parts have been 

 reduced to one part 800 cubic feet squeezed down to 1 cubic foot. 

 In addition to compressing it has to be cooled. This is done by al- 

 lowing a small portion of highly compressed air to suddenly expand 

 in a tube that surrounds the tube in which the compressed air is 

 confined. By repeating this process the air is made so cold that it 

 finally liquefies at a temperature of 312 degrees below zero, Fahren- 

 heit. In so compressing and cooling the air it was found necessary to 

 first filter it, to take out all impurities and to dry it thoroughly, because 

 any water left in it, and we all know that air contains considerable 

 moisture, would freeze and the particles of ice would interfere with the 

 process. So that liquid air is perfectly dry (although it looks just 

 like water) and much purer than the air usually is. In his public ex- 

 periments Prof. Tripler often spills some liquid air (accidently, of 

 course) upon some lady's rich fine gown and he greatly enjoys the 

 look of consternation and the little scream " Oh! you've ruined my 

 dress." Mr. Tripler usually steps nearer as if to see, and says, 

 " Where?" and then throws on some more. But, of course, no spots 

 and no dampness can be seen, for the air is dry and evaporates the 

 instant it is thrown. 



Although so very cold it may be stirred with the finger safely. 

 This is explained in the same way as a drop of water on a red-hot 

 stove. Instead of instantly evaporating it will roll or dance around 

 for a while. This is because owing to the difference in temperature 

 a portion of the drop of water fcrms a vapor which prevents actual 

 contact. The great difference in the temperature of the finger and 



