93 



dredths of milk of lime at 20 B is added thereto, 

 and is properly mixed, then carbonic acid gas is 

 introduced. At the same time it is gradually heated 

 up to about 200. Again it is watched to notice the 

 time when to shut off the injection of carbonic acid, 

 and when it is seen that the liquid when drawn out 

 is clarified instantly, the operation is complete. 

 The carbonic acid is however left to act for a few 

 minutes to ensure more complete success, then the 

 injection of gas is shut off, and the liquid is boiled 

 for a moment to drive off the excess of the carbonic- 

 acid retained and the juice is again sent to be de- 

 canted, the juice is this time sent to the filters. 



The froth or deposits from the decantation pass by 

 a juice lifter which sends them into the press filters. 



The clear juice drawn from the press-filters goes 

 through the second carbonatation. 



3. FILTERING. 



The juice runs into the filter and fills it to the 

 height of the overflow tap which is the same as the 

 upper surface of the charge of the filter. In this 

 manner is regulated the duration of the contact of 

 the charcoal with the juice, which is an important 

 point ; the animal charcoal acts not only as a mecha- 

 nical filtering agent, but also as an absorbent, and 

 the lunger the contact of the charcoal with the juice 

 is prolonged, the more does the charcoal produce 

 its effects by absorbing the azote substances, coloring 

 matter, lime and salts. The entrance and discharge of 



