846 



METHODS OP KINETIC MEASUREMENTS 



CHAP. 25 



bubbles to larger ones, effect of convection currents or stirring on the size 

 of bubbles and similar complications. A number of authors (Kohl 1897 

 Kniep 1915, Wilmott 1921, Bose 1924, Arnold 1931, among others) have 



Fig. 25. 3A. "Warburg apparatus" for manometric measurement of photosynthesis. 



Scale In Ccnfimetcrs 



Fig. 25. 3B. Two "Warburg vessels" with equal liquid volume but differ- 

 ent gas volume (after Emerson and Lewis 1941). 



strived to improve this method and to make the bubble counting automatic; 

 a discussion of these attempts can be foimd in Spoehr's book (1926, page 

 231). An important objection has been raised by Gessner (1937): Con- 

 stant size bubbles can only be formed in quiet water, where a photosynthe- 



