148 matured /llMractes* 



stitution, London, succeeded in liquefying not 

 only oxygen but atmospheric air. And be- 

 sides liquefying the air he made ice of it. 



In 1892 I visited London, where I met Pro- 

 fessor Dewar, who invited me to witness an 

 exhibition of the manufacture of liquid oxy- 

 gen and incidentally liquid air at the Eoyal 

 Institution. To me it was a most wonder- 

 fully interesting event. I saw air, taken from 

 the room, gradually liquefy in a small glass 

 test tube open at the top. When the tube was 

 withdrawn from the refrigerating chamber it 

 boiled by the heat of the room, and rapidly 

 evaporated. We lighted a splinter of wood 

 and blew it out, leaving a live spark on the end 

 of it, and held it over the mouth of the tube, 

 knowing that if anything like pure oxygen 

 were evaporating the splinter would relight 

 and blaze (an old experiment with oxygen 

 gas). At first the splinter would not relight, 

 because the evaporating gases were a mixture 

 of oxygen and nitrogen in the proportions to 

 form air. But owing to the fact that nitro- 

 gen evaporates sooner than oxygen, a second 

 trial was successful, for the splinter imme- 

 diately began to blaze, showing that the gas 

 evaporating then was pure, or nearly pure, 

 oxygen. 



When the liquid oxygen was poured into a 

 saucer and brought into proximity with the 

 poles of a powerful magnet the liquid imme- 



