MANUFACTURE OF WOOD-VINEGAR. 



223 



into the fire-place. The pipe conducting the wood-vinegar and 

 the tar into the vats h dips somewhat into the fluid. From the 

 vats the fluids are pumped into large reservoirs placed at a, 

 higher level, so that they can be readily discharged into the stills. 



The apparatus is not movable, i. e., the retort remains fixed in 

 its place. 



Movable retorts, as shown in Fig. 50, were first introduced in 

 France. They are entirely surrounded by the fire gases, the fire- 

 place being closed on the top by a brick cover held together by 

 means of iron hoops. The vapors and gases pass out through 

 the pipe a which is placed on the side immediately below the 

 cover. When no more volatile products appear the lid is removed, 



Fig. 50. 



and, after interrupting the connection with the condenser, and 

 closing the pipe a with clay, the glowing retort is lifted out by 

 means of a crane. A new retort already filled with wood is then 

 immediately placed in the hot furnace and distillation recom- 

 menced. The pipe b conducts the non-condensed vapors and 

 gases into the fire-place. 



In modern times this apparatus has been modified, as shown in 

 Fig. 51, and in this form is in general use in France. The de- 

 veloping pipe for the volatile products has been transferred to the 



