For an inferior army Portugal has no defensible frontier. The rivers, generally running east and west, are fordable in most places, subject to sudden rises and falls, offering but weak lines of resistance; and with the exception of the Zezere, presenting no obstacles to the advance of an enemy penetrating by the eastern frontier. The mountains, indeed, afford many fine and some impregnable positions, but such is the length of the frontier line and the difficulty of lateral communications, that a general who should attempt to defend it against superior forces would risk to be cut off from the capital, if he concentrated his troops; and if he extended them his line would be immediately broken. The possession of Lisbon constitutes, in fact, the possession of Portugal, south of the Duero, and an inferior army can only protect Lisbon by keeping close to that capital. Sensible of this truth, sir John Cradock adopted the French colonel Vincente’s views for the defence of Lisbon; and proceeded, on the 4th of January, with seventeen hundred men to occupy the heights behind the creek of Saccavem--leaving, however, three thousand men in the forts and batteries at Lisbon. [Sidenote: Sir J. Cradock’s Correspondence, MSS.] At the earnest request of the regency, who in return promised to assemble the native troops at Thomar, Abrantes, and Vilha Velha, general Stewart’s brigade, two thousand seven hundred strong, was ordered to halt at Santarem. But it had been marching incessantly for a month, and in the rain, the men’s clothes were worn out, their accoutrements nearly destroyed, and in common with the rest of the army, they were suffering severely from the want of shoes. Thus, Cameron being on the Douro, the main body between Santarem and Lisbon, and colonel Kemmis at Elvas, with the fortieth regiment, an army of ten thousand men--with the encumbrances of an army of forty thousand--was placed on the three points of a triangle, the shortest side of which was above a hundred and fifty miles. The general commanding could not bring into the field above five thousand men; nor could that number be assembled in a condition for service at any one point of the frontier, under three weeks or a month; moreover, the uncertainty of remaining in the country at all, rendered it difficult to feed the troops, for the commissaries being unable to make large contracts for a fixed time, were forced to carry on, as it were, a retail system of supply.