They can very easily be introduced without changing the form or general character of the works, and they are really so very essential that, without them, a fort constructed 25 or 30 years ago, and well suited to the then existing state of the military art, will be likely to offer no very considerable resistance to modern siege batteries or well organized maritime attacks.
Some have gone much further in their estimate of the effect produced by the increased size and force of military projectiles, and boldly assert that masonry works of strong relief can no longer be used, and that the increased range of small arms requires an entire change of the bastioned front, with lines more extended.
With respect to the effect of the increased range of small arms, it is very natural that a superficial observer should adopt the opinion that this improvement must be followed by an extension of the lines of a defensive military work; but a close study of the subject will probably lead to a different conclusion.

Such at least is the opinion of the ablest military engineers of Europe.

The lines of the bastioned front now generally in use, were really too long for a good defence with the arms in use at the time it was adopted; and, in theory, the "rampart gun" was to be relied upon for the defence of certain exposed points.
But this weapon is no longer in use; its place, however, is better supplied by the increased range of the musket and rifle.

The latter weapon is almost invaluable for defending the approaches to a permanent work.
With respect to the breaching of stone masonry by siege batteries, it has long been an established principle that all masonry exposed to the fire of land batteries should be masked by earthen works.

The neglect of this rule caused the fall of Bomarsund.