228 



VINEGAR, CIDER, AND FRUIT-WINES. 



free expansion, sits loosely in a slightly conical socket. The 

 lower end of the last pipe divides into two branches, one of 

 them leading downward and dipping into the receiver, while the 

 other, as a rule, conducts the gases directly under the fire-place. 

 There should be but a small space between the collecting pipe , 



Fig. 55. 



which conducts the vapors to the condenser, and the first conden- 

 sing pipe, as otherwise obstructions might readily be formed by 

 the deposit of tar dried by the hot vapors. A constant stream of 

 water is conducted through 6, along the bottom of the trough, 

 the heated water running off at c. 



The development of gas from the wood being very irregular 

 and by no means in the proportion desirable for the heating of 

 the retorts, it is preferable to collect it in a gasometer and distrib- 

 ute it from there as may be necessary, instead of conducting it 

 directly into the fire. But little gas is developed in the beginning 

 of the operation, and much towards the end, while the reverse 

 proportion is desirable. 



In case condensation is not very complete, the pipe leading to 

 the hearth or gasometer is more or less attacked by acetic acid 

 precipitated in it by the access of air. To prevent this evil it is 

 advisable to place on the pipe small receptacles provided with 

 cocks for the collection and discharge of any fluid deposited. 

 These receptacles may also be filled with quick lime, which at 

 least fixes the acetic acid, thus rendering it harmless for the pipe. 

 The lime is from time to time extracted with water to regain the 

 soluble calcium acetate. 



To further cool off the current of gas and render the vapors of 

 acetic acid carried along with it harmless for the pipe, Vincent 



