The fall of Vicksburg and the openng of the Mississippi River from 8t. Louis to the Gulf of Mexi;o, cuts the rebel confederacy into two equal parts, the area west of that river being almost exactly the sanie as that east. This will be seen better by the following figures: Square Miles. Area of Arkansas, 52,198 Area of Louisiana, 41,255 Area of Texas, 237,00-1 330,057 That is the territory cut off. The following is what remains: Alabama, 50,722 Georgia, 58,000 Mississippi, 47,156 South Carolina, 29 385 North Carolina (four-fiftbe), 40 600 Virginia (two-thirds), 41,000 Tennessee (one half), -110,000 329,663 The effect of this severine of the confederacy cannot be otherwise than most disasfrous to tho rebel prospect; Either section alone is too small and insignifioant to undertake to maintain an independent government ; and with the Mississippi onc3 in our posaeision, it will be our own fault if any portion of it ever comes under the swuy of he socalled eonfederaoy during the rernainder of its brief existonce.