Adeney — Dissolved Gases and Fermentative Changes. 547 



each lialf c. c. was withdrawn. The neck being graduated in this way, it was 

 possible to note immediately before displacing the disengaged gas, which was 

 done over distilled water, the volume of water which would enter the flask and 

 become mixed with its contents ; the capacity of the flask, with the stopper 

 inserted, and the composition of the gases dissolved in the distilled water being 

 known, it was in this way possible to calculate and correct for the error which the 

 admission of the distilled water into the flask would introduce in the estimation 

 of the dissolved gases in the liquid under experiment. 



The form of apparatus which I have used for extracting the dissolved gases, 

 measuring and analj'sing them, is shown in the accompanying drawing. It 

 consists of a mercury-pump combined with a gas analysis apparatus, and can be 

 used for all three operations required in the examination of the gases dissolved in 

 liquids, viz. for their extraction, measurement, and complete analysis. The 

 remaining parts of the apparatus which are shown in the sketch consists of 

 a Liebig's condenser of glass, and a round-bottomed stout glass flask ^vith a side 

 tube from the neck.* 



The flask, which for convenience of reference I propose to name the laboratory 

 flask, is made of sufficiently stout glass to bear a vacuum. The only points of 

 importance, so far as shape is concerned, are that it must be round-bottomed, and 

 that the neck must be somewhat long and tapering to allow of the short india- 

 rubber cork, by which the inner tube of the condenser is packed air-tight into it, 

 fitting sufficiently deep down to leave a space above itself for a water or mei'cury 

 luting. 



The capacity of the flask should be about four times the volume of liquid 

 to be boiled in it. It is convenient to have two sizes, viz. 1500 c. cs., and 

 2500 CCS. 



The laboratory flask is employed for conducting the necessar}' operation of 

 boiling the liquid under examination in vacuo, for the extraction of the gases 

 dissolved in it. Since the condenser to which it is attached cools down, and 

 condenses the aqueous vapour given off during the process of boiling, the liquid 

 may be heated to violent ebullition continuously for any required length of 

 time without fear of unduly raising the pressure of the vapour and gases in the 

 flask. 



The gas analysis apparatus proper, shown in the drawing, is an improved 

 form of that which I have already described in a Paper, published in the 

 " Scientific Proceedings of the Royal Dublin Society."t To that Paper I would 



* The glass parts of the apparatus were obtained from Messrs. Baird and Tatlock, of Grlasgow and 

 London. 



f " On an Apparatus AppKcahle for Gas Analysis and Other Purposes." — Scien. Proc. R. D. S., vol. vi., 

 pt. ix., p. 555 (1890). Eeprinted in the " Chem. News," 62, pp. 196-199, and 204-206. 



TRAlfS. EOT. DUB. SOC, N.S. VOL. V., PART XI. 41 



