DISTILLATION OF STUMPWOOD. 35 



at 100 to 125 C., and free flowing at about 125 to 150 C. It is 

 practically devoid of taste or odor, and dissolves readily in turpen- 

 tine, but only very sparingly in either cold or hot alcohol, differing in 

 this respect from common or black rosin. Its acid value was found 

 to be 2, extracted with alcohol, against 150 to 180 for black rosin. 



It differs from what is purchased under Government contracts for 

 " North Carolina pitch " in being, on the whole, blacker, and some- 

 what softer, and in having, therefore, a generally lower melting 

 point. It is believed, however, that this will not detract from its 

 value in the uses previously enumerated, but rather that its somewhat 

 greater pliability may be found to be advantageous. 



CHARCOAL. 



The charcoal obtained in these experiments from western yellow 

 pine, especially that from the richer or more resinous samples of 

 wood, is very soft and friable It retains an appreciable amount of 

 bituminous matter, due undoubtedly to incomplete distillation, which 

 causes it to burn with a long, smoky flame. Its possible application is 

 suggested in industries where powdered fuel is used, or in metallurgi- 

 cal operations in which the crushing strength is not a prime requisite. 



The charcoal from " bull " pine was in every respect superior to 

 that obtained from yellow pine proper, and, in general, the quality 

 of the charcoal fell off as the rosin content of the wood increased. 

 Compared to that from hardwood, the western yellow-pine char- 

 coal must be considered of inferior quality, especially as to hardness. 



Tamarack charcoal has a much denser structure and is not so 

 friable as that obtained from yellow pine. Moreover, it is clean or 

 free from bituminous matter, and appears to be quite similar to hard- 

 wood charcoal. 



ACID LIQUOR (PYROLIGNEOUS ACID). 



The specimen log of a run (page 27) shows that an aqueous dis- 

 tillate which is nearly pure water comes over with the turpentine at 

 the beginning of a distillation and is rejected. As the heating is 

 continued, the wood tissue begins to decompose and the aqueous 

 liquor takes on a straw color. From this point it contains acids and 

 alcohol in varying quantities, and constitutes a true acid liquor, 

 which in these experiments was retained and examined. 



The acid liquor results from chemical transformations of bodies 

 making up the wood tissue and rosin contained in the wood, brought 

 about by heating the wood to a sufficiently high temperature. This 

 reaction is a true chemical process, none of the compounds found 

 in the liquor occurring in the untreated wood. The action is alto- 

 gether different, therefore, from the recovery of turpentine and pine 

 oils, the separation of which is effected by a physical change of 



