The Count de Pagan 60 Fathoms. Monsieur de Vau∣ban forms it according to the Plurality of the Bastions. As you may see Lib. 3 c. 17.
As to the Figure of the Curtains there are some Engineers, who will have them ••o be, as is mark'd at the Letter A; of which the Construction is such. See the Plate P. Fig. XXII. at the end of the third Book.
1. Divide the Line AB into •• equal parts, as AD, DM, NC, and CB, and take •• for the Demi-Gorge, as BC, AD.
2. Divide the same Line AB into three equal parts, and take one for the Capital, as BE, A••.
3. Where these three Parts are marked, as at R and G, bring down from the Points R, G, two Perpendiculars, of which se•• each have the third part of the Capital Line for its length, as RH and GI, and then joyn H and I toge∣ther by a Right Line.
4. Make upon the Points D and C, the Angle of the Cur∣tain of 100 degrees, and allow to the ••lank the length of the Demi-Gorge, •••• DP and CQ. This being done, joyn EQ and DP together, to have the Faces. The defects of the Curtain are, 1. That it is too short. 2. That the ••ortification takes up too much room. 3. That it renders the Bastion too Acute.
Others there are that form an Angle without side, as that which is marked with the Letter B. The Construction of which is after this manner.
1. Divide the Line AB into five equal parts, as AC, CD, DE, EF, and FB.
2. Divide the first Line AB into three equal parts, and allow one for the Capital, as AI, and BK; then join HI and BK together, to gain the Faces.
3. Divide the Curtain CF into two equal parts, and up∣••n the middle, marked with the Letter L, erect a Per∣pendicular; which has the half of the Face GK; as LM.
4. Draw from CF two streight Lines to the Point M, and your Curtain will be made. See the Plate P. Fig. XXIV.
••••hers make the Curtain of a C••rcular Figure within••s••de,