STUDIES ON FERMENTATION. 361 



merited on must be treated out of contact with air, by aspirating 

 it directly from tlie vessel that contains it into the pipette H, 

 which is graduated for 50 c.c, and causing it to pass thence 

 into the flask E, by substituting the pipette for the funnel a. 

 Finally, before arranging the pipette, we cause a small quantity 

 of the liquid in the flask, which has been previously brought to 

 the exact yellow tint, to pass, by pressure, through the tube eb, 

 so as to avoid the cause of error that is likely to result from the 

 air held in solution in the liquid of that tube. 



The liquid, the ox3'gen of which has to be determined, may 

 also be passed directly from the vessel containing it into the 

 flask E ; the rest of the operation being performed as already 

 described. 



It was by this method that the oxygen held in saturate solu- 

 tion in wort was determined. The following are the principal 

 results obtained by M. Raulin : — 



1. At difierent pressures the ratio between the quantities of 

 oxygen held in solution in water and in wort is, all other con- 

 ditions being similar, constant. This ratio has been found equal 

 to 1*20 in the case of wort and water saturated with air at the 

 ordinary pressure, and 1*24 in the case of wort and water 

 saturated with pure oxygen. 



2. The ratio between the coefficient of the solubility of 

 oxygen in water and that of its solubility in wort is very nearly 

 constant at different temperatures, increasing, however, slightly 

 as the temperature diminishes. 



This ratio has been found to be — 

 Temperatures. 



26° C. (78-8° F.) 1-20 



19-5° C. (67-1° F.) 1-25 



4° C. (39-2° F.) 1-37 



Another wort gave the following results : — 

 Temperatures. 



9°C. (48-2° F.) 1-15 



21° C. (69-8° F.) 1-10 



25° C. (77-0° F.) 1-07 



