PITCH, a tenacious oily substance, drawn chiefly from pines and firs, and used in shipping, medicine, and various other arts: or it is more properly tar, inspissated by boiling it over a slow fire.
The method of procuring the tar, is by cleaving the trees into small billets, which are laid in a furnace that has two apertures, through one of which the fire is put, and through the other the pitch is gathered, which, coming from the wood, runs along the bottom of the furnace into places made to receive it. When the smoke, which is here very thick, gives it blackness, this is called tar; which, on being boiled, to consume more of its moisture, becomes pitch.
There is another method of drawing pitch, used in the Levant: a pit is dug in the ground, two ells in diameter at the top, but contracting as it grows deeper; this is filled with branches of pine, cloven into shivers; the wood at the top of the pit is then set on fire, and burning downwards, the tar runs from it out of a hole made in the bottom; and this is boiled, as above, to give it the consistence of pitch.