Caí uo, July 5. The ratn Monarch brings news trom Viuksburg of the 28th uit, Ou Thursday Porter's fleet comineuced to shell the upper battery below tho town. This contiuued all day without result, and was rencwed ou Friday, and in the afternoun it wa8 directed ou the towu, over which the shells were plaiuly seen to burst. - This continued until four, when it ceased. During the bombardmeut the rebel batteries replied feubly ; thoir firing was inaccurate. Half an hour after the cessation of the bombardment, the rebel water battery opened on the mortar flect, whieli replied uutil tho batti'ry ceased firing. - At eight in the cvening the fire opened from the eutire fleet unon tho town, and eoutinued au hour. The next morniug at four o'clock the bombardmeut was reuewed, during whioh eight of Farragut's vessels passed tho butteries without serious dauiage. Tho city must havo been greatly damaged. - The couflagration was seen in uumerous places. We are informad on indisputable authority that 3,000 negrcfes have been ordered by Gen. Butler to work on the canal across the beüd on whioh Vicksburg or its remains are now situated. - The channel of the Mississippi will thus be changed, nnd Vicksburg will become an inland towu hereafter. Several hundi-ed more shcll have been crdcred from New Orleaus to reduce the remaius of the p'ace to ashes.