440 On exlracimg Vinegar from Wood. 



The water wb.ich is in the wood soon dissipates, and the 

 carbonization begins. Then there is disengaged a good deal of 

 carbonic acid ; acetic acid combined with water ; Carbonated 

 hydrogen ; and an oily matter similar to tar, with perhaps a 

 small portion of carbonic acid gas. 



From part of the retort in which the decomposition is made, 

 all these matters are forced to pass through the entire mass of 

 wood to get to the opening of the pipe before mentioned, wiiich 

 is purposely placed at the inferior extremitv; by this pipe they 

 enter into the copper cylinder which conveys them to the con- 

 denser; there almost all that is water, the acetic acid and oily 

 matter become condensed, and run off through the little cock ; 

 vvhile all the carbonic acid, the carbonated hydrogen gas, car- 

 bonic acid gas, which also carry with them a small quantity of 

 the other products, rise up by the other cylinder, and go into 

 the fire, where thev serve as fuel. 



When this operation has continued five hours, these inflam- 

 mable vapours are directed, by means of a cock, under the fire of 

 another retort, just lighted ; the heat of the first furnace, and 

 that which escapes from the wood during its decomposition, 

 being sufficient to complete the carbonization of all which is 

 contained in it, without the aid of the combustion of the gas. 

 It is not necessary even to wait till the evaporation of these va- 

 pours has ceased, before the tube is removed from the ash-pit of 

 the first furnace, because the charcoal would be too weak. 



As soon as the neighbouring retort begins to give out its 

 gaseous products, and can do without further assistance, the 

 pipe is removed from the ash-pit, and the remaining gas which 

 comes out is ignited, in order to prevent the disagreeable smell 

 arising from it. The flame thus produced is as large as the pipt', 

 rises many feet above the pipe, and lasts about half an^hour. 

 The moment the retort is removed, it is replaced by another, 

 and the same process is observed as with the former. 



Caution however is required in this process ; for the moment 

 the retort is taken out of the furnace, the copper cylinder 

 is filled with inflammable gas : if it is joined and luted imme- 

 diately to that which succeeds it, the gas will mix with the air 

 contained in it, and the very smallest spark that could possibly 

 penetrate the fissures of the retort would occasion an explosion ; 

 for which reason the apparatus is never to be luted till the very 

 iu'^tant of the appearance of the empyreumatic vapour. 



Th.c retorts are from about seventy-two to a lumdred cubic 

 feet in capacity. They contain one and a half to two loads of 

 wood, which, when it is well chosen and of a good quality, will 

 yield twenty-eight per cent, of charcoal, and yield two hundred 



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