208 



VINEGAR, CIDER, AND FRUIT- WINES. 



Fig. 48. 



Determinations of acetic acid by titration having to be fre- 

 quently executed in a vinegar factory it is advisable to use an 

 apparatus which will facilitate the operation. Such an ap- 

 paratus is shown in Fig. 48. Upon a table stands a two-liter 

 flask holding the normal soda solution. The 

 flask is closed air-tight by a cork provided 

 with three perforations. In one of these per- 

 forations is inserted a glass-tube, A, in the 

 lower end of which is a stopper of cotton upon 

 which are placed small pieces of burnt lime. 

 On top, the tube is closed by a glass-tube drawn 

 out to a fine point. Through another of these 

 perforations passes a glass-tube, jR, bent twice 

 at a right angle and reaching to the bottom of 

 the flask ; the portion of this tube outside of 

 the flask, as will be seen in the illustration, is 

 somewhat longer than that in the flask, and, 

 consequently, the tube forms a siphon. The 

 outside portion of this tube is connected by a 

 short rubber tube with the upper portion of 

 the burette B. The latter is secured in a ver- 

 tical position by two rods placed on the stand 

 holding the flask. Below the burette is con- 

 nected with a short rubber tube in which is in- 

 serted a glass-tube drawn out to a fine point. 

 On the side near the top of the burette is a small tube bent at a 

 right angle, which is connected by a short rubber tube with the 

 tube L, the latter reaching only to below the edge of the cork. 

 Above and below the burette is closed by the clips Q and Q L . 



For working with the apparatus the flask is filled with normal 

 soda solution and the cork inserted air-tight after removing from 

 it the tube A and substituting for it a small glass-tube. Now 

 open the upper clip Q and blow vigorously through the glass- 

 tube substituted for A, whereby the fluid is forced through the 

 tube R into the burette. This being done cease to press upon Q, 

 whereby the latter closes and stops a further discharge of the 

 fluid. The tube, A, is then placed in position. By now pressing 

 on the clip Q the fluid passes into the burette, the air contained 



