358 



STUDIES ON FERMEXTATIOX. 



solution of ammonia of sucli strength that about ten drops of it 

 will neutralize the acidity in 50 c.c. (1-76 fl. oz.) of wort. 



To perform the operation we shake about 150 c.c. (5'3 fl. oz.) 

 of distilled water, at the existing temperature, in a 1-litre flask 

 for a minute or so ; this saturates it with air, and we must at 

 the same time note the temperature. To be extremel}' precise, 

 Ave should note also the barometrical pressure. 



Into the bottle E we introduce about 50 c.c. of the indigo 

 solution, and 200 c.c. of water at about 60° C. (140° F.), and 





Fig. si. 



fill the tube e to the point h with water saturated with air ; we 

 then expel the air from the bottle E by a current of hydrogen. 



