10 HOME MADE ICE. 



touched with a lighted match on the end of a long rod the sponge ex- 

 plodes with violence and is torn to shreds. 



Iron and steel become brittle as glass. Gold, silver, copper and 

 aluminum are not affected. Lead becomes stiff and elastic like steel. 

 Mercury becomes solid, like iron. Ivory, cooled in liquid air, and 

 then held in a strong light, is seen to glow with a bright phosphores- 

 cence. 



The anomaly of burning a steel pen in this very cold liquid is 

 shown in Fig. 2. This shows a tumbler with liquid air about one-half 

 evaporated and hence, rich in oxygen. If, now, an ordinary steel pen 

 or a watch spring is held in the liquid and touched with a lighted 

 match, the steel burns with the brilliancy of an electric arc. In the 

 early experiments at preserving liquid air, a glass bulb was used, 

 around which a large bulb had been blown (See Fig. 8) and the air 

 exhausted from the space between. The liquid lies quietly in such a 

 bulb without boiling. In an ordinary bulb (Fig. 9) it boils con- 

 stantly while the outside of the bulb is quickly covered with ice the 

 frozen moisture from the air. An entire volume could be written on 

 the marvels of this fluid, which sooner or later is destined to hold a 

 prominent place in the economy of human existence. 



Value Of Liquid Air Gases. Prof. Raoul Pictet, the Swise> 

 scientist, claimed that with a comparatively simple apparatus he could 

 dissociate or separate the constituent gases of liquid air so that with B 

 500 horse-power steam engine at a total cost of $74 per day he could 

 make and separate enough liquid air to obtain daily 3,550,000 cubic 

 feet of oxygen, 5,300,000 cubic feet of nitrogen and 3,000 pounds of 

 carbonic acid, and that the present total value of all these gases was 

 over $1,500. 



HOME MADE ICE. 



Ice Made With Chemicals. Ice can always be purchased 

 cheaper than it can be produced in a small way, but sometimes it is 

 desirable to secure extreme cold or to make ice when it is inconvenient, 

 or when there is no time to go to the places where ice may be pur- 

 chased. In such cases ice can be made in a suitable vessel by the use 

 of nine parts of sodium phosphate and four parts of dilute nitric acid, 

 or by equal parts of ammonium nitrate and water. A stronger mixture 

 is the following: 



Phosphate of soda 9 parts 



Nitrate of ammonia 6 " 



Dilute nitric acid 4 " 



By means of this solution it is possible to reduce the temperature 

 from 50 Fahrenheit to 21 Fahrenheit. 



To freeze water by either of these mixtures, one only needs a small 

 dish, the narrower the better (it should not be over two inches wide) 

 to hold the water to be frozen and a larger dish fitting more or less 



