250 



Scientific Proceedings, Royal Dublin Society. 



been shown' that a litre of a normal solution of ammonium chloride only contains 

 007 c.c. of dissolved oxygen, and, if this substance can readily be prepared in 

 a suitable form, it would probably prove satisfactory. On the other hand, 

 ammonium chloride dissolves ^^'ith absorption of heat, while potash evolves heat 

 on solution, and this might militate against ammonium chloride as compared 

 with potash, since heat evolution undoubtedly greatly accelerates the displace- 

 ment of gas. 



Description of Apparatus. 



The final form of apparatus used is shown in the fig-ure. is a capillary 

 3-way mercurjr-sealed tap, joined to a tube AB of 25 to 3 mm. bore. This is 



joined to a bulb of 20 to 30 c.c. capacity, connected by a short tube of about 

 1 cm. bore to a vessel of the shape shown, about 9 cm. long by 4 cm. in diameter. 



' MacArthur, J. Phys. Chem., 20, 495, 1916. 



