The cotemporaries of Chasseloup were mostly engaged in active field service and sieges, and few had either leisure or opportunity to devote themselves to improvements in permanent fortification. Choumara published in 1827. His system contains much originality, and his writings give proof of talent and genius. He has very evidently more originality than judgment, and it is hardly probable that his system will ever be generally adopted in practice. The Metz system, as arranged by Noizet, as a theoretical study, is undoubtedly the very best that is now known. It, however, requires great modifications to suit it to different localities. For a horizontal site, it is probably the most perfect system ever devised. It is based on the system of Vauban as improved by Cormontaigne, and contains several of the modifications suggested by modern engineers. It is applied in a modified form to the new fortifications of Paris. Baron Rohault de Fleury has introduced many modifications of the ordinary French system in his new defences of Lyons. We have seen no written account of these works, but from a hasty examination in 1844, they struck us as being too complicated and expensive. The new fortifications of Western Germany are modifications of Rempler's system, as improved by De la Chiche and Montalembert. It is said that General Aster, the directing engineer, has also introduced some of the leading principles of Chasseloup and Carnot. The English engineers have satisfied themselves with following in the track of their continental neighbors, and can offer no claims to originality.