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THE ROYAL SOCIETY OF CANADA 



the gas mixture in question. This sensitive element, which is used in 

 conjunction with a pointer indicator (See Plate II) or a galvanometer, 

 is called a Katharometer^ or an explorer, and is illustrated in Plate I. 



We are indebted to the Cambridge Scientific Instrument Co., 

 Ltd., the makers of the instruments, for permission to reproduce 

 Plates I and II, and also Fig. I. 



The electrical bridge arrangment used with the katharometer is 

 shown in Fig. 1. In this diagram, S and E are switches, D a 2-volt 

 accumulator, C two sliding resistances for rough and fine adjustment 



C/= r€sista>tces 



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Figure 1 



