542 



JOHN R. MURLIN 



of Boston an average value of 0.031 per cent for carbon dioxicl arid 20.038 

 per cent for oxygen. In one series of 340 analyses nearly equally divided 

 among 18 Haldane analyzers of the type described in Fig. 10 Boothby 

 and Sandiford found the average CO 2 in the air taken upon the 

 fire escape of their laboratory in the middle of Rochester, Minn., to be 





Fig. 20. The air analyser of Krogh. This apparatus like that of Zuntz and 

 Geppert employs separate burettes for measurement of the air before and after 

 absorption of CO 2 and oxygen. The air is moved from one burette to another by 

 means of air pressure. For details of operation consult the original article. 



0.037 per cent and the oxygen 20.030 per cent. In a second series of 343 

 analyses the average was 0.035 and 20.030 per cent. The higher percentage 

 of CO 2 they ascribe to the fact that a large number of chimneys in the 

 neighborhood of the laboratory gave out smoke which often drifted toward 

 the laboratory. 



