74 



Composition of the Atmosphere 



Fig. 1. Sonden air-analysis apparatus. 



The two pipettes A and B, and the reagent containers C and D, are immersed in water in the 

 glass tank. Stop-cocks a, b, c, and d, permit intercommunication of all parts. Cabron- 

 dioxide percentages are read directly on A, and oxygen percentages directly on B. Mercury 

 reservoirs F and E are connected with pipettes A and B respectively. The manometer M aids 

 in securing equal tension in A and B. 



