FOR ( 260 ) FOR

short of that extensive knowledge, whichevery military man, who aims at militaryfame, must be ambitious of acquiring.Chains of mountains, and volumes ofwater, together with the influence whichdifferent climates have upon the latterelement, should always constitute a partof the natural system that ought to forman essential portion of his application.Hydrography will likewise assist him inthis pursuit. To enlarge upon this im-portant, branch of geography, and topoint out the great means which it af-fords of natural defence and offence infortification, would exceed the limitsof our present undertaking. We shall,therefore, refer our military readers toBelair’s Element de Fortification , and

content ourselves with submitting a shortaccount of the different authors who haveeither given original systems, or havegreatly unproved those that were alreadyknown. Independent of whom, maybenamed the following writers, who havelikewise contributed to the general know-ledge of fortification, viz. Muller, llobins,Beiidor, Cormontagne, Tolard, Clairac,Le Blond, Dedier, Marshal Saxe, Cugnot ,Tielke, Landsbergen, Trincano,’ Fallios,Ros'ird, Belair, ike.

Fortification, according to the me-thod of Pagan , consists in three differentsorts, viz. the great , the mean, and thelittle, whose principal dimensions arecontained in the following

T,\iH.r.

The great Fortification.

The mean.

The little.

for squares

for ail poly-gons

for squares

: for all poly-

gons

for squares

for all poly-

gons

Exterior side

200

200

180

180

160

160

The perpendicular

27

30

24

30

21

30

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

For other dimensions in his differentmethods, such as the magnitudes of thediminished angles, the flanked or salientangles, the angles of the tenailles oroutward flanking angles, and the exactlengths expressed in toises of the linesof defence, of the complements of theselines, of the tenailles, of the flanks of thecurtains, the perpendicular distancesfrom the intersections of the lines of de-fence to the curtains, and the perpendi-cular distances from the exterior sides tothe curtains, see Glenie’s Military Con-struction.

Blondel fortifies within the given po-lygon : he establishes two sorts of for-tification ; the great one, whose exterior

side is 200 toises, and the lesser one 170 {because he will not have the line of de-fence exceed 140’ toises, which is thegreatest musket-shot, nor less than 120toises, not to increase the number ofbastions. He begins by the diminishingangle, which may be found by taking90 degrees from the angle of, the poly-gon, and by adding"! 5 degrees to thethird of the remainder. For exact ge-neral expressions of the magnitudes ofthe angles diminucs, the flanked angles,the outward flanking angles, and theangles of the epaules or shoulders, inthese methods, &c. see Glenie’s MilitaryConstruction.

Vauban’s method is divided into little,