A military dictionary

by William Duane

Fortification, according to the method of Pagan, consists in three different sorts, viz. the great, the mean, and little, whose principal dimensions are contained in the following

Table.

The great Fortification.					The mean.				The little.
	for squares		for all other polygons		for squares		for all other polygons		for squares		for all other polygons
Exterior side	200		200		180		180		160		160
The perpendicular	?7		30		24		30		21		3?
The face	60		60		55		55		45		50
The flank	22		24	2	19	1	24		18	3	23	2
The curtain	73	2	70	5	63	4	60	4	63	5	50	4
The line of defence	141	4	141	2	126	1	126	5	115	5	112	3

Blondel fortifies within the given polygon: he establishes two sorts of fortification; the great one, whose exterior side is 200 toises, and the lesser one 170; because he will not have the line of defence exceed 140 toises, which is the greatest musquet shot, nor less than 120 toises, not to increase the number of bastions. He begins by the diminishing angle, which may be found by taking 90 degrees from the angle of the polygon, and by adding 15 degrees to the third of the remainder.

Vauban’s method is divided into little, mean, and great: the little is chiefly used in the construction of citadels; the mean, in that of all sorts of towns; and the great, in particular cases only.

Table.

	Forts.							Little.				Mean.		Great.
Side of Polygon	80	90	100		110	120	130	140	150	160	170	180	190	200	260
Length of perpendicular	10	11	12	¹⁄₂	14	15	16	20	21	23	25	30	31	25	22
Faces of Bastions	22	25	28		30	33	35	40	42	45	47	50	53	55	60
Capital of Ravelins	25	28	30		35	38	40	45	50	50	52	55	55	60	50

In the first horizontal row are the numbers expressing the lengths of the exterior sides from 80 to 260.

In the second, the perpendiculars answering to these sides.

In the third, the lengths of the faces of the bastions; and in the fourth, the lengths of the capitals of the ravelins.