On the other hand, Melas within the rectangle had the advantage of interior lines. He could therefore, other things being equal, concentrate his forces more quickly upon any side than could Bonaparte. Should he learn in time where Bonaparte would enter Italy, he could defeat the French divisions in detail as they issued from the passes of the Alps. But in order to take advantage of his central position, he must be accurately informed of Bonaparte's movements. He must fathom his adversary's designs; otherwise the advantage of position could avail him nothing. Thus it is seen how the element of surprise became such an essential factor in these operations, and how important it was that Bonaparte should deceive the Austrians as to his real intentions. The success of the entire plan, the fate of Italy itself, hinged on this fact. It was the first great step towards success; it was the entering wedge to victory. Long before the campaign opened, Bonaparte saw clearly this fact. In the midst of untiring activity at Paris, while momentous questions were engaging his attention, he contrived the stratagem that deceived his adversary, and worked out the details that led ultimately to his triumph at Marengo. Already some of the advantages which the possession of Switzerland gave to Bonaparte have been pointed out. It will now be noticed that he could safely assemble a large force in this almost impregnable stronghold, and could debouch therefrom upon the rear of the Austrians in Italy. In this way he could descend upon the Austrian communications with little danger of losing his own with Switzerland. Even should the army of Italy be driven back to the line of the Var, as long as the French held this river and the French Alps on one side of the Austrians, and Switzerland on the other, Bonaparte had the advantage of an angular base, from either side of which he could march to attack the Austrians in Italy. In fact, the possession of Switzerland, extending east from the French frontier, gave to Bonaparte the advantage of an angular base in his operations against either Kray in Germany or Melas in Italy. Moreover, Switzerland offered him a secure place where he could assemble his forces and strike either Austrian army a vital blow. Upon these facts was based not only the plan of campaign that decided the fate of Italy, but that grander conception which offered still greater results. As previously stated, the Austrian plan of campaign was that Kray should remain on the defensive in Germany, while Melas took the offensive in Italy. There were several reasons for adopting this plan. First: Austria had in the preceding year been remarkably successful in northern Italy. Step by step she had driven the French from the Adige to the Apennines. Being anxious to hold what she had conquered, and hoping to continue her success in Italy, she gave Melas one hundred and twenty thousand soldiers, and directed him to take the offensive against Masséna.