APPENDIX II TO CHAPTER V 157 



the ends. The upper part of the flask is cooled by water, which 

 is enclosed by a lead wall partially shown at I. For greater 

 security the india-rubber cork is also drowned in water, held in 

 place with the aid of sheet-lead. The lower part of the globe 

 is occupied by about 3 litres of a 5 per cent, solution of caustic 

 soda, the solution rising to within about half-an-inch of the 

 platinum terminals. In a successful experiment 9250 c.c. of 

 air were used and 10,820 c.c. of oxygen were consumed, the 

 proportion of oxygen being to nitrogen as 1'75 to 1*0, that is, 

 more than sufficient to convert the nitrogen into nitrous acid, 

 in which form it is absorbed. The argon ultimately left after 

 absorption of the excess of oxygen amounted to 75 c.c., or a little 

 more than 1 per cent, of the atmospheric " nitrogen " used. 

 (Phil Trans, vol. 186, part I A, p. 212 to p. 219.) 



