In 1767 De la Chiche introduced a system of fortification in many respects original. He raised his covered-ways so as to conceal all his masonry, and casemated a great portion of his _enceinte_. For exterior defence, he employed direct fire from his barbettes, and curvated fire from his casemates; the direct fire of the latter secured his ditches. Next to De la Chiche follows Montalembert, who published in 1776. He was a man of much experience and considerable originality, but of no great ability as an engineer. Most of his ideas were derived from De la Chiche and the German school of Rimpler. His plans have generally been rejected by his own countrymen, but they still have advocates among the Germans. General Virgin, a distinguished Swedish engineer, wrote in 1781. His idea of strongly fortifying the smaller towns to the comparative neglect of the larger cities, constitutes one of the principal novelties in his system. In 1794, Reveroni devised a system in which the casemates of Montalembert were employed, but his guns were so arranged as to be employed in barbette while the besiegers were at a distance, and afterwards to be used for casemated fire. The casemate gun-carriage, which formed a part of his invention, was ingenious, but never much employed in practice. Bousmard, a French emigrant, published in 1790. He adopted the general trace of Vauban, but introduced modifications in the details essentially different from those of Cormontaigne. Some of these modifications are very valuable improvements, while others are of a more doubtful character. Bousmard is, on the whole, a very able writer, and his works should be found in the library of every military engineer. Carnot's celebrated treatise was published in 1810. He was evidently a man of genius, and during his career at the head of the War Department of France, numerous and very important improvements were made in the several branches of the military art, and especially in strategy. His work on fortification exhibits much originality and genius, but it is doubtful whether it has very much contributed to the improvement of this art. His ideas have been very severely, and rather unfairly criticised by the English, and particularly by Sir Howard Douglas. Chasseloup de Laubat early distinguished himself as an engineer of much capacity and talent. He followed Napoleon in nearly all his campaigns, and conducted many of his sieges. He remodelled the fortifications of Northern Italy and of the Lower Rhine. He published in 1811. The improvements which he introduced are numerous and valuable, and he probably contributed more to advance his art, and to restore the equilibrium between attack and defence, than any other engineer since Cormontaigne. After the fall of Napoleon and the partition of his empire, the allies mutilated or destroyed the constructions of Chasseloup, so that, it is believed, no perfect specimen of his system remains.