466 



HISTORY OF THE VEGETABLE KINGDOM. 



ditch, the wliole is coated with clay, and beaten 

 hard; on this are piled the cut branches and 

 pieces of wood divested of their baric. The 

 wood is piled up so as to form a tmncated and 

 inverted cone; the whole is then strewed with 

 pine leaves, and covered with earth, a few holes 

 being left for air. Fire is commxinicated to the 

 top, and a gradual and confined combustion is 

 produced downwards to the base. As the tar 

 Hows into the ditch, it is emptied out into casks 

 ready for receiving it. 



The American tar is reckoned inferior to that 

 of the north of Europe, probably from using 

 dead wood, and less care being employed in its 

 manufacture. 



Dr Clarke thus describes the method of distil- 

 ling tar in the gulph of Bothnia: "The process 

 by which the tar is obtained is very simple : and 

 as we often witnessed it, we shall now describe 

 it, from a tar-work which we halted to inspect 

 upon the spot. The situation most favourable 

 for this process is in a forest near to a marsh or 

 bog; because the roots of the fir, from which tar 

 is principally extracted, are alwaj's the most 

 productive in such places. A conical cavity is 

 then made in the gi-ound (generally in the side 

 of a bank or sloping hill); and the roots of the 

 fir, together with logs or billets of the same, 

 being neatly trussed into a stack of the same 

 conical shape, are let into this cavity. The whole 

 is then covered with turf, to prevent the volatile 

 parts from being dissipated, which, by means of 

 a heavy wooden mallet, and a wooden stamper, 

 worked separately by two men, is beaten down 

 and rendered as firm as possible above the wood. 

 The stack of billets is then kindled, and a slow 

 combustion of the fir takes place, without flame, 

 as in making charcoal. During this combustion, 

 the tar exudes; and a cast-iron pan being at the 

 bottom of the funnel, with a spout, which pro- 

 jects through the side of the bank, barrels are 

 placed beneath this spout, to collect the fluid as 

 it comes away. As fast as the baiTels are fiUed, 

 they are bunged and ready for immediate expor- 

 tation. From this description, it will be evident 

 that the mode of obtaining tar is by a kind of 

 distillation per descensum; the turpentine, melted 

 by fire, mixing with the sap and juices of tlie 

 fir, while the wood itself, becoming charred, is 

 converted into charcoal. The most curious part 

 of the story is, that this simple method of 

 extracting tar is precisely that which is described 

 by Theophrastus and Dioscorides; and there is 

 not the smallest difference between a tar-work 

 in the forests of Westro-Bothnia, and those of 

 ancient Greece. The Greeks make stacks of 

 pine; and, having covered them with turf, they 

 were suffered to burn in the same smothered 

 manner; while the tar, melting, fell to the bottom 

 of the stack, and ran out by a small channel cut 

 for the purpose." 



m. 



The Pitch Pine (p. rigida), is common 

 throughout the United States, but is most abun- 

 dant on the Atlantic coast. It is a very branchy 

 tree, and the wood is consequently knotty. It 

 is very resinous, and affords a large quantity of 

 pitch. The bark is thick, of a dark colour, and 

 deeply furrowed. The concentric circles of the 

 wood are far asunder; and three-fourths of the 

 larger stocks consist of sap. On high ground 

 and light gravelly soils, the wood is heavy and 

 full of resin; on low humid soils it is the reverse, 

 and unfit for use. 



The White Pine (p. strdbm). Tliis is one of 

 the most valuable and interesting species of pines, 

 is common to Canada and the northern parts of 

 the United States, and has its distinctive name 

 from the perfect whiteness of its wood when 

 fireshly exposed. The leaves are five-fold, four 

 inches in length, numerous, slender, and of a 

 bluish green. The cones are four to five inches 

 long, and composed of thin, 

 smooth scales, rounded at the 

 base. It grows extensively 

 between the parallels of 43° and 

 47° in almost all varieties of soil; 

 but attains its gi-eatest dimen- 

 sions in the upper part of New 

 Hampshire, the State of Ver- 

 mont, and near the source of the 

 St Lawrence. This ancient and 

 majestic inhabitant of the North 

 American forests, is still tlie 

 loftiest and most valuable of their 

 productions; and its summit is 

 seen at an immense distance 

 aspiring towards heaven, far 

 above the heads of the surround- 

 ing trees. The trunk is simple 

 for two-thirds or tliree-fourths 

 of its height; and the limbs are short and verti- 

 cellate, or disposed in stages one above the other 

 to the top of the tree, which is formed by three 

 or four upright branches. This tree is the fore- 

 most in taking possession of barren districts, and 

 the most hardy in resisting the impetuous gales 

 from the ocean. On young stocks not exceeding 

 forty feet in height, the bark of the trunk and 

 branches is smooth and polished; as the tree 

 advances in age it splits and becomes nigged, 

 but does not fall ofl^ in scales like that of the 

 other pines. The trunk also tapers and lessens 

 from the base to the summit, more than those 

 of the others of the same tribe. The wood is 

 soft, light, free from knots, easily wrought, and 

 very durable when exposed to the air and sun; 

 on these accounts it is much employed in domestic 

 use, a great proportion of the houses in the 

 northern States being built of it. 



It is also largely exported to Britain, where 

 it is much used in domestic architecture. The 

 wood is not resinous enough to furnish turpeu- 



Cone of W'liite 

 I'ine. 



