Of the system of fortification now followed in our service we must decline expressing any opinion; the time has not yet arrived for subjecting it to a severe and judicious criticism. But of the system pursued previous to 1820, we may say, without much fear of contradiction, that a worse one could scarcely have been devised. Instead of men of talent and attainments in military science, most of our engineers were then either foreigners, or civilians who owed their commissions to mere political influence. The qualifications of the former were probably limited to their recollection of some casual visit to two or three of the old European fortresses; and the latter probably derived all their military science from some old military book, which, having become useless in Europe, had found its way into this country, and which they had read without understanding, and probably without even looking at its date. The result was what might have been anticipated--a total waste of the public money. We might illustrate this by numerous examples. A single one, however, must suffice. About the period of the last war, eight new forts were constructed for the defence of New York harbor, at an expense of some two millions of dollars. Six of these were _circular_, and the other two were _star forts_--systems which had been discarded in Europe for nearly two thousand years! Three of these works are now entirely abandoned, two others are useless, and large sums of money have recently been expended on the other three in an attempt to remedy their faults, and render them susceptible of a good defence. Moreover, a number of the works which were constructed by our engineers before that corps was made to feel the influence of the scientific education introduced through the medium of the Military Academy--we say, a considerable number of our fortifications, constructed by engineers who owed their appointment to political influence, are not only wrong in their plans, but have been made of such wretched materials and workmanship that they are already crumbling into ruins. A fortification, in its most simple form, consists of a mound of earth, termed, the _rampart_, which encloses the space fortified; a _parapet_, surmounting the rampart and covering the men and guns from the enemy's projectiles; a _scarp wall,_ which sustains the pressure of the earth of the rampart and parapet, and presents an insurmountable obstacle to an assault by storm; a wide and deep _ditch_, which prevents the enemy from approaching near the body of the place; a _counterscarp wall_, which sustains the earth on the exterior of the ditch; a _covered way_, which occupies the space between the counterscarp and a mound of earth called a _glacis_, thrown up a few yards in front of the ditch for the purpose of covering the scarp of the main work.