MANUFACTURE OF WOOD- VINEGAR. 



225 



conducting channel are reopened. When after about one hour 

 the water is expelled from the wood, and acid vapors appear, a 

 copper pipe is connected with the condenser, and the joints made 

 tight by a clay luting. The gases appearing in constantly in- 

 creasing abundance during distillation, are now conducted under 

 the second retort in order to heat it sufficiently towards the end 

 of the distillation, as otherwise the charcoal will show " brands, " 

 i. e. y pieces not entirely carbonized. 



A retort holding 2 cubic meters (70.63 cubic feet) of wood is 

 distilled off in 8 hours. 



Horizontal retorts. Generally two wrought iron retorts are 

 placed in one fire-place, for instance, 6 retorts in three fire-places 

 with a common chimney, as shown in Fig. 52, one-third to two- 

 thirds of their circumference being, as a rule, bricked in. In front 

 and back they are closed by cast-iron disks, the front one being 



Fig. 52. 



movable so that, when an operation is finished, it can be readily 

 removed, and replaced. From the back disk a pipe leads to the 

 condensing apparatus. For the back disk is sometimes substi- 

 tuted a conical shoulder which ends in a pipe about 8 inches in 

 diameter to which the discharge pipe is secured (Fig. 54). 



Each cast-iron retort has a special fire-place, and the cylindrical, 

 as well as the rectangular retorts, are bricked in only at the bot- 

 tom. The brickwork is held together by several iron clamps. 

 The retorts rest upon the arch above the fire-place in such a man- 

 ner that they are not directly struck below by the flame but only 

 surrounded by it from the side and above. It is also advisable 

 to expose, not only the cylindrical space holding the retorts to the 

 fire, but also the annexed conical one. The narrow pipe projects 

 about one foot above the wall. 

 15 



