An important reason why the Italian army should prefer the Riviera road into France with all its perils was that, apart from the natural difficulties of the Alpine routes, which had rather increased than diminished since the time of Hannibal and Cæsar, they were unwilling—such was their loyalty to public law—to expose themselves to the charge of infringing the neutrality either of Switzerland or of Savoy. For it must be remembered that, even after it had changed hands with Nice in 1860, Savoy, this section, so to speak, of the Franco-Italian Alsace-Lorraine, continued subject to the Treaty of Vienna (1815) as neutral territory, part of which, Chablais and Faucigny, might even be occupied with Federal troops ‘in the event of Switzerland’s neighbours being in a state of open or imminent warfare.’ Indeed, a portion of the Federal Army had already made bold to brave the displeasure and even the reprisals of France by occupying as it was, theoretically speaking, entitled to do, the upper part of Savoy; and this had introduced into the military situation an element of complexity which the Italians would have been foolish to ignore. Consequently, they resolved to force the passage of the Riviera road—the more so as their fleet could cover their march to some extent, and even land troops at particular points, as long at least, at the other portions of the French navy, at present engaged in the Baltic and elsewhere, should not be free to make for the Mediterranean. The Italians had also resolved to send another smaller army, consisting of their 1st and 3d Corps (whose places in the army of the Riviera were to be taken by the 6th and 8th), across the Alps by the Mont Cenis route, so as thus to attempt to turn the flank of the French Army, consisting mainly of the 7th, 14th, 15th, and 16th Corps, which were now pretty well all the French could spare from the further draft they had had to make on their military resources with a view to repair their reverses on the Rhine. BATTLE OF COSTEBELLE. MOUNTAIN WARFARE.