Affairs In The Southwest

A correspondent of the N. Y. World gives the following items of interest froiy the Southwest : The base line of oporations. ngalnsfc the enemy is at present the lino of th,e Mem phis and Charleston road, exteudini eastward as far as luka. The hostile force under General Pemberton issituated along the banks of the Tallahatohie Rivor, forty miles distant. The regicp between that streara and an intermedíate stream - the Cpldwater - is at preseut occupied by their cavalry and may be oonsidered a kind of dinputed territory, to be yielded whenever our infantry shall advanee, until then to be scouted over by the cavalry of' cither party. TIip most reruarkable feature of tbis campaign in the West is the perfeetion and eompieteness of the railroad s3Tstsin of conveyance. This army moves by railroad ; and it oan move aa rapidly, more easily, more safely, and more cheaply than by the combined resources of mulo and horse-flesh Never before were railroads brought into sush ooinplete requisition. Tlie roads have to be thoroughly repaired, aid in some instances alrnost reconstruoted, as the army moves and yet tho rate of progress is quite equal to that of an army traveling after the old fashion. To the ballooD, the telegrapb, and the army bakery, the locomolive has been added as an implcment of warfare, and we now have un army advaricing by cars - its scouting done in mail .lad trucks, its roconnois-ances made by loeomotives. Watertanks, switche, rajls, ties, trestlework, bridges, wheels, eating saloons, everything is provided as if by private coinpany Froui tho material side the aspect of the war is more civilized than ever. and we may add, by so mueh the more effeetive Aa a corollary to this movement on the part of Gen. Grant'sforces it is to be presutned that General Hosecrans will keep sharp wateh upon the movements of Gen BraL'g's army, which at latest accounts is moving on Chattanooga. This pluces our forci's in the sanje posit'iou of July last, nnt, we trust, to resul t in a similar deuouement. The route which Gen. Bragg must take to reinforce Pembertoii bis easiest, though certainly a very long route - is by ruil from Chattanooga to Atlanta, Georgia; thenoe to Montgome.y, Selma and Meridian, where he su-ikes the Jackson llüilroad. The Httlo link betweeti Selma and Montgomery, Alabama, of less than twenty miles, was not completud up to a recent period, but was in course of coustruction. This movement would leave Hosecrans ranster of Chat tanooga, and consequently of the great trunk route from tho southircst to jlichinond, a point of great importance. - That once gained, the half of his army oeuld be rushed down the Mississippi to Memphis or Vicksburg, along the road to Mobile, or concentrated with the army of Gr&nt,