The war of 1688 commenced with the siege of Philisbourg, where the Dauphin commanded in person, and Vauban directed the attacks. He here tried the effect of firing _en ricochet_, of which he was the original proposer. The superiority of this method of attack was not so decisively shown in this first instance as on subsequent occasions: still it proved so far effectual in subduing the fire of the town, as to cause its surrender after twenty-four days of open trenches. The Duc de Montausier said in a letter to the Dauphin, “I do not offer you my congratulation on the fall of Philisbourg: you had a good army, mortars, guns, and Vauban.” On the same occasion, Louis XIV. wrote thus to the successful engineer:—“You know, long since, in what estimation I hold you, and the confidence I have both in your knowledge and affection. Believe that I do not forget the services you render me, and that I am particularly pleased with your conduct at Philisbourg. If you reciprocate the feelings of my son you must be on the best of terms, for I feel assured that he, equally with myself, knows how to esteem and value you. I cannot conclude without earnestly recommending you to preserve yourself for the benefit of my service.” Manheim and Franckenthal were next besieged and taken. On the surrender of the latter, the Dauphin presented Vauban with four pieces of artillery, to be selected by him from the arsenals of the conquered fortresses, to ornament his chateau of Bazoches. He was this year promoted to the rank of Lieutenant-General. The difficulty with which the obstacles presented at the siege of Philisbourg were overcome, induced Vauban to renew, with greater earnestness, his project for the formation of a corps of sappers, originally suggested shortly after the peace of Aix-la-Chapelle. Louvois, though he yielded to Vauban’s arguments in favour of this new force, postponed its formation, and subsequent events prevented his adding this to the other establishments which he created.