1'rof. C. Timiriazeff. 



[Apr. 30, 



The main object was to alter, so to speak, the scale of the gasometrie 

 measurements without altering the precision of the method and the 

 convenience of all the operations. Though I have often since that 

 time changed the details, the principle of the method I adopted 

 remains the same. The leaves are introduced into cylindrical tubes of 

 suitable diameter, or still better into flat tubes in order to increase the 



FIG. 1 . 



green surface, and the gases are measured and analysed in a tube of 

 the smallest possible bore. All the necessary manipulations, the 

 transfusion of gases as well as the treatment by liquid re-agents, are 

 easily performed by using this form of gas pipette, which I introduced 

 in 1871, and still (fig. 1) consider the most convenient. The gas pipette 

 and the mercury trough are rigidly connected, allowing us to give to 

 the ascending branch of the syphon an outer diameter not exceeding 



