THE PROBLEM OF FORTIFICATION. 91 



image of the first movements of the besieger, who wants 

 to get possession of a fortress by a regular attack. The 

 ground represents the Sultan's carpet.* His life is 

 endangered unless he advances under cover ; but let 

 him dig the earth ; let him heap up the rubbish in front 

 of him ; let him unceasingly roll up a little of the carpet 

 as he advances ; and behind this movable shelter the 

 besiegers, carrying with them a powerful artillery, ap- 

 proach the ramparts of a fortress very soon in full force, 

 without being seen by the besieged. 



The problem of fortification may, indeed, be consid- 

 ered at bottom as a particular case of the geometrical 

 theory of polygonal stars. This assemblage, apparently 

 so inextricable, of salient and of reentering angles, of 

 bastions, of curtains, of demilunes and tenailles, &c., of 

 which modern fortresses consist, is the solution of the 

 very old question of flanking. We may in some points 

 vary the construction, but the aim is always the same. 

 The abstract principles of the art have become clear and 

 evident. The illustrious corps of officers who at the 

 present day are at liberty to apply them to the defence 

 of the country, have had the good sense to abandon the 

 mystery with which it was before surrounded, and with 

 which it has been so severely reproached. Fortification 

 is taught like other sciences ; it is founded on the most 

 elementary geometry ; a mere amateur can familiarize 

 himself with the theory in a few lessons. 



* This is scarcely a "faithful image," and unless the story could 

 be improved, it is hardly worth preserving. The gradual increase of 

 labour and cover in advancing, and the total absence of cover at the 

 commencement, are features foreign to a regular siege; there cover 

 is obtained at first, and they go steadily on, making no more or less 

 than the requisite cover all the way. The story, however, might be 

 applied to an old fortress with very lofty towers, which would require 

 more cover as you got nearer. Translator. 



