2⁰ũ Tie gen vſt Als cam

85 1. 1„ 9—

Firſt, we may protract tliis Fort, by making a Square i hoſe Side A Bchall be 300 foot by the Scale: then take but 14 for che Gorge, and ſetthem off from A unto D, and from R unto H: at D and H raiſe twoFlanks perpendicular te the Sides of the Fort, and there prick down 100from D unto E, and from H unto G. That done, take 33 out of theſame Scale, and ſetting one foot of the Compaſſes in the point E, make anoccult Ark of a Circle. Again, ſetting one foot of the Compaſſes in thepoint&, make another occult Arë, croſſing the former in the point F;So che Lines E E, EG ſhall repreſent the Face of the Bulwark.

In like manner for the Bulwark at B, we may ſet off the Gorge fromB unte N,&. So have we divers Triangles, which may be reſolved by

che firſt three Propoſitions of right lined Triangles: and the manner ef

it hall be ſo ſet down, as that Precept may be eaſily diſtinguiſhed fromche Example, and applied to any other, not only by this Canon andTable of Logarithms, but by the old Canon of Sines and Tangents, andby che Lines of Sines and Tangents both upon the Sector and theCroſs ſtaff. f e

1. In the Rectangle A D E, baring the Sides AD, AE, we mayfind che Angles at A and E, and the third Side A E, by the former part a

of the third Proportion of Right-Iined Triangles.As