CH. n] TIMIRIAZEFF'S EUDIOMETER 47 



then transferred 1 to the vessel of water in which E 

 stands, and the gas in G is poured up into the funnel F 

 at the lower end of E. The funnel is connected with the 

 graduated part of the tube by a capillary passage, so 

 that the gas transferred from the carrier remains in the 

 funnel, whence it is drawn into the eudiometer by pulling 

 out the glass rod R working like the piston of a syringe. 

 The gas having been measured by means of the gradua- 

 tions on E, the piston is pushed in and the bubble forced 

 down into the funnel F. 



The pipette P is dilated into a bulb at B and ends 

 below in a bent capillary tube which can be inserted into 

 the funnel of the eudiometer, when by drawing out the 

 pistons of the syringe at the upper end of P, the gas is 

 drawn into the pipette. For estimation of oxygen the 

 pipette contains freshly made solution of potassium pyro- 

 gallate 2 . After two or three minutes, the gas is returned 

 to the funnel of the eudiometer, drawn in by the eudio- 

 meter syringe, and once more measured. The difference 

 between the first and second readings of the eudiometer 

 gives the amount of oxygen absorbed by the pyrogallate : 

 the whole operation is so quickly done that no corrections 

 for barometric or thermometric changes are necessary. 

 Timiriazeff's apparatus cannot with any approach to 

 accuracy be employed for estimating the C0 2 in a sample 

 of gas. 



1 The analysis of gas given off by water plants may also be made in 

 the Bonnier-Mangin apparatus described in Exp. 5. 



2 0-4 gram pyrogallic acid in 20 c.c. of KOH (3050 p. c. solution). 



