FIrst take the Diameter of the Piece upon the thickest Part, at the Breech of the Gun, with a Pair of Callaber Compasses, and see upon the Quadrant of your Callabers, how many Inches that is ; the half of which Diameter take between a Pair of Compasses, and put that distance off upon a Sheet of Cartridge-Paper, which will make two Points upon the Paper, as A and B ; then take the Diameter of the thickest part with your Callabers, and see how many Inches that Diameter is, And take the half thereof between your Compasses, and set one Foot in A, and the other Point in C upon the said Line AB, at C.

Then take the Distance from C, to B, on the Line, and that is the true Dispart of the Piece ; and if you take a Stick or Straw of that length, and set on the Muzzle fastned with Wax, it will be a true Dispart for that Piece.