412 CONIFERS. 



as the thinnings, by the time they are twenty years old, 

 are of size sufficient to cut into staves for making the 

 barrels in which the smoked or red herrings and other 

 dried fish are packed. Throughout the whole of the coasts 

 of Scotland and the North of England, they also afford 

 the chief supply of pit props, consumed in enormous quan- 

 tities by the collieries of the Tyne and the Wear, and are 

 now beginning to be employed in forming the wooden 

 pavement lately introduced into the streets of the metro- 

 polis. For most of the above uses, a crop of Scotch fir 

 may be obtained from soils too poor to bring even the 

 larch to a marketable size. 



In Britain the resinous products of the Pine are seldom 

 turned to any account, but upon the Continent, in Sweden, 

 Norway, Russia, &c, the greater proportion of the tar of 

 commerce is procured by a kind of dry distillation of the 

 Pine, the wood being subjected to a slow combustion as 

 in making charcoal, when the tar, which exudes from it 

 in the form of a thick, blackish brown liquid, is conducted 

 into vessels or barrels so placed as to receive it. The 

 tar, when it is wished to convert it into pitch, is boiled 

 slowly and for some time in large copper vessels, after 

 which it is let out, and as it cools hardens into that 

 substance. Turpentine, also, but of an inferior quality 

 to that procured from the silver fir, is obtained by strip- 

 ping off a piece of bark from the trunk of the tree in 

 spring, when the sap is in motion, and the resinous juice 

 that exudes is received in a notch or hollow cut in the tree, 

 at the bottom of the canal formed by removing the strip 

 of bark ; this juice, as it accumulates, is ladled out into 

 a basket, and the liquid that passes through the interstices 

 is the common turpentine. The residue, or thicker matter 

 that remains behind, is then put into a common alembic 



