594 Prof. Kia-Lok Yen on the Coefficients of 



In fig. 4 is shown the arrangement of the generating and 

 purifying apparatus, which was also made of a continuous 

 piece of glass work throughout. The flask A contained the 

 dry Na 2 2 , while the bulb B contained distilled water into 

 which a small amount of potassium permanganate had been 

 dissolved in order to serve as catalyser. After the apparatus 



Fio\ 4. 





CH S_ 



T*i 



Mil 



T, 



A 



* 



A 



■ 

 1 



Tz 



^ S 7 



c— -To M&c- 



^\ /.eoei 



E give, 







D 



M 



was thoroughly evacuated the water was caused to drop 

 slowly through the stopcock S upon the chemical, and 

 reaction was thus started and the evolution of gas begun. 

 The gas thus generated passed through a wash-bottle 

 containing concentrated sulphuric acid, then through a 

 tube containing lumps of KOH, and then through the 

 coil T l into the pyrex tubes containing Ca and CuO. 

 These tubes were heated up to about 500 degrees centi- 

 grade. Thereafter the gas passed through a* battery of 

 P 2 5 tubes and then entered the coil T 2 , where it was 

 liquefied. This was accomplished by immersing the coil T 2 

 in ;i vessel of liquid air. 



When a reasonable amount of gas was thus liquefied the 

 evolution of the gas was stopped by the stopcock S. The 

 stopcock Si was then closed. Theta the liquid-air vessel was 

 removed from under T 2 and placed under T 1? and thus the gas 

 liquefied in T £ was allowed to boil and return, in its gaseous 

 state, through the purifying agents into the coil T 1? where it 



