562 



Adeney — Dissolved Gases and Fermentative Changes. 



The capacity of the bottle was 2530 c.cs. Dividing the volumes of oxygen and 

 nitrogen by 2-53, vv^e get the volumes of these gases disengaged, per litre of water, 

 at the time of the conclusion of the experiment. These volumes are : — 



Oxygen, 



Nitrogen, 



0-40 c.cs. 

 1-91 



The results of the analysis of the gases* dissolved in the water at the commence- 

 ment and conclusion of the experiment are given in full in the following Table : — 



No correction was made for the distilled water introduced into the bottle when 

 collecting the disengaged gases. 



The changes in volume of the carbon dioxide and oxygen shown in the above 

 Table were no doubt due to the fermentation of small quantities of peaty 

 colouring-matter which the tap-water contained, and not to experimental errors. 

 This explanation is supported by the increased quantity of nitrate found in the 

 water after keeping. 



The gaseous nitrogen, however, remained unchanged in volume during the 

 period of keeping, and the difference between the volume of this gas found before 

 and after keeping indicates the probable value of the total error from the two 

 distinct sources mentioned above. 



Before leaving the consideration of errors due to variation of temperature of 

 the solutions during the time of keeping them, I ought perhaps to point out that a 

 disengagement of dissolved gases on rise of temperature is more or less completely 

 prevented under the ordinary conditions of my experiments, since a considerable 

 pressure was always kept up in the bottles when the temperature was rising, by 

 keeping them resting with their full weight upon their stoppers. 



This I have generally found sufficient to prevent the stoppers from becoming 

 too freely loosened by the expanding force of the water under the influence of rise 

 of temjierature. I should add that care has been taken to guard the solutions 

 against any serious daily variations of temperature, and the precaution of re- 

 tightening the stoppers from time to time has also been taken, 



* Volumes of the gases are expressed in c.cs., at N.T.P., per litre of water. 



