STUDIES ON FERMEKTATION. 373 



boiled the wort ; and during ebullition we sealed the end of the 

 fine tube. After it had cooled, we arranged that pure air 

 should enter the flask. To do this we made a file mark near 

 the fine closed point of the flask, and connected the point by a 

 piece of india-rubber tubing with a glass tube containing a 

 column of asbestos, which we heated. We then broke ofi" the 

 point of the flask inside the india-rubber tube, so that the air 

 entered the flask after being filtered through the asbestos. We 

 removed the india-rubber tube and sealed up once more the 

 fine end of the neck at the point where we had broken it ofi". 

 Finally, to aerate the wort to saturation, we shook the flask 

 briskly for some minutes, and then placed it in a hot-water 

 bath, where we left it for about a quarter of an hour. We 

 afterwards removed it to an oven at 25° (77° F.). We repeated 

 the same operation next day and the four succeeding days. 



The wort, which at first was scarcely coloured, gradually 

 assumed a reddish-brown tint, and deposited an amorphous 

 matter, but without brightening. It became clear, however, 

 when filtered, which was not the case with the turbid, opaline 

 wort in the bottles when they arrived. 



The following is an analysis of the air in the flask, made 

 immediately after a renewed and vigorous shaking, the object 

 of which was to saturate the wort with air before analyzing the 

 supernatant air : — 



November 29tli. 



Temperature at whichi 

 the flask was refilled 



with air 4° C. (29-2° F.) 



Atmospheric pressure . 7ol mm. (29'6ins.) 



Total volume of flask 333 c.c. (20-32 cub. in.) 



Volume occupied by the wort .. .. 120 ,, (7*32 ,, ) 



December 8th. 



Volume of gas analyzed 27'6 c.c. (1"68 cub. ins.) 



After treatment with potash 27*4 c.c. (1'67 ,, ) 



pyrogallol . . . . 22-4 „ (1-36 „ ) 



Oxygen o-O c.c. (0- 305 cub. in.) 



