The Seventh _Corps d'Armée_, commanded by the Duke of ALBUFERA, formed the basis of the Army of the Alps. It did not at that time amount to more than 15,000 men; but arrangements were made for its augmentation, by the end of June, to 40,000 men. It held the passes along the Italian frontier--was strongly posted at Grenoble, and at Chambery--communicating on its left with the First Corps of Observation; and covering the approach to Lyons, where very extensive works were carried on with the utmost vigour and activity. The First Corps of Observation, called the Army of the Jura, commanded by Lieutenant General LECOURBE, guarded the passes along the Swiss frontier; had its Head Quarters at Altkirch, and occupied the line between Huningen and Belfort--communicating on its right with the Army of the Alps, and on its left with the Army of the Rhine. It did not, at that time, consist of a larger force than 4,500 men; which, however, was to be augmented to 18,000 on the arrival of additional Battalions from the National _Guard d'élite_ then in course of active organisation. The Second Corps of Observation, called the Army of the Var, commanded by Marshal BRUNE, had its Head Quarters at Marseilles; occupied Toulon and Antibes, and watched the frontier of the Maritime Alps. Its force, which then amounted to 5,300 men, was to be joined by sixteen Battalions of the National _Guard d'élite_; and, in this way, increased to 17,000 men. The Third Corps of Observation, called the Army of the Eastern Pyrenees, commanded by Lieutenant General Count DECAEN, had its Head Quarters at Perpignan. It did not then consist of more than 3,000 men; but was to be augmented by thirty-two Battalions of the National _Guard d'élite_ to 23,000 men. The Fourth Corps of Observation, called the Army of the Western Pyrenees, or of the Gironde, was commanded by Lieutenant General CLAUSEL; had its Head Quarters in Bordeaux; consisted of the same force as that of the Third Corps; and was to be augmented in a similar manner. The Army of La Vendée, commanded by General LAMARQUE, was occupied in restoring tranquillity to that part of the Empire. It consisted of about 17,000 men, including Detachments supplied temporarily from the Third and Fourth Corps of Observation. Arrangements had also been made for reinforcing, at the end of June, the two Armies of the Rhine and the Alps, with 50,000 men from the troops of the Line organised in the Regimental Depôts, and with 100,000 men from the National _Guard d'élite_; and with a view to afford a Second Line and Support to the Grand Army, commanded by NAPOLEON in person, the latter was to be augmented by 100,000 men of the National Guard, and by 60,000 men of regular troops taken from the Depôts, where the additional Battalions and Squadrons of Regiments were in course of daily organisation. * * * * *