GIRT

, in Timber-measuring, is the circumference of a tree; though some use this word for the quarter or 4th part of the circumference only, on account of the great use that is made of it; for the square of this 4th part is esteemed and used as equal to the area of the section of the tree; which square therefore multiplied by the length of the tree, is accounted the solid content. This content however is always about one-fourth part less than the true quantity; being nearly equal to what this will be after the tree is hewed square in the usual way: so that it seems intended to make an allowance for the squaring of the tree.

Girt-Line, is a line on the common or carpenter's sliding rule, employed in casting up the contents of trees by means of their Girt.