262 ELEMENTS OF SYLVICULTUEE . 



I visited at Mont de Marsan several distilleries. 

 In one of them they distil the resin for spirits of 

 turpentine. The raw resin always contains, accord- 

 ing to the care with which it has been collected, a 

 greater or less quantity of impurities, such as lumps 

 of earth, chips of wood, bark, leaves, &c. To remove 

 these the resin is put into boilers, in which it is 

 subjected to a temperature just high enough to 

 liquify it without causing it to volatilise. In this 

 liquid state it is passed through sieves of rye-straw 

 into troughs. The clear liquid is known under the 

 name of tertfbentkine. From the troughs the 

 terebenthine is conducted through apipe supplied 

 with a stopcock into a still. During the distillation, 

 a thin continuous stream of water is introduced into 

 the retort by means of a funnel. The water, in the 

 state of steam carries over with it the spirits of tur- 

 pentine, and after condensation in the worm they are 

 both received into a vat. They are then separated 

 by the process of decantation. Colophony and black 

 and white rosin are made from what remains in the 

 retort. A conduit-pipe leads this residue into a 

 trough, whence it is passed through a very fine brass 

 sieve into a wooden chest ; what is collected in the 

 chest is colophony ; what is left behind in the sieve 

 is black rosin. It is made into cakes of from 100 to 

 200 Ibs., by pouring it while liquid into troughs 

 hollowed out in fine sand. White rosin is prepared 

 in the same way, except that the hot residue in the 

 sieve is agitated briskly in one-tenth its volume of 

 water before it is poured out into the sand moulds. 



All these products have their special industrial 



