84 



known to the writer for practical work. The large central opening- 

 permits the operator to take the temperature of the must, or remove 

 samples for examination at pleasure without displacing- the entire 

 apparatus, and it can be quickly and perfectly cleaned. 



A third device (tig. 17), also of German origin, answers a good pur- 

 pose, especialh" in laboratory work, but it is not recommended for 

 cellar work. This is called the g-lycerin control tul)e. It is made of 

 glass, and is operated by inserting- the stem through a ])ung {'/). Gh^- 

 cerin or one of the liquids mentioned above is introduced at the fun- 

 nel (h) until the bulb {d) is half 

 full. The principle is exactly 

 the same as with the previous 

 devices. Should the pressure 

 decrease in the vessel air can 

 enter through the liquid b}' 

 reason of the enlargements {d 

 and ('). The enlargement (e) 

 permits the escape of gas from 

 the vessel without driving out 

 the control liquid. 



A very simple device is 

 shown in ligure 18. This con- 

 sists simply of a bent tube in- 

 serted in a perforated bung, 

 the outer end being so placed 

 that it rests below the surface 

 of the liquid in a basin. This 

 device is very faulty because 

 if, for any reason, pressure 

 decreases in the cask the liquor 

 from the basin will be drawn 

 into the must. In practice the 

 best devices are found to be 

 of the greatest assistance in 

 indicating the activity of the 

 fermentation. To the practiced operator they become at once the 

 barometer which warns him of danger or assures him of the proper 

 progress of fermentation. 



Fig. 17.— Glycerin ventilating funnel. 



VENTILATING BUNGS AND SPIGOTS FOR CASKS. 



In connection with the yu])ject of fermentation funnels, the use of a 

 ventilating bung should be mentioned. After the first fermentation 

 has subsided and the liquor has been placed in casks for the second 

 fermentation, it is desirable to close the casks tightly — at least so as to 

 exclude as far as possible the entrance of air. Yet in so doing one 



