This, the largeat and most important Fortress in the United States, in being reservcd to the general government iu this contest with our Southern rebellion, gives to our government an immense degiee of power in the vork of restoring Virginia to the tJnion. The fortress, oonipletely cornmnndingthe outlet to James river - which is the inlet to Norfolk and Richmond - oommands also the she'ter of f blockading squadron for the outlet of Oaesupjako B;iy ; ho that holding snid fort the government, in locking up ihe bay, oan, without dii' ticulty, eompletely lock up all the navigabk' tratera of Virginia and ol Manland for any length of time. The fortress covers some sixty-iive acres of grotind, and is defended by four hundreu gunsof heavy calibre, requiiing a was garrison of twunty-ftve liuDdred men. Over three thousand aro now within its walls, ana nine thousand more wil! soon be added for outside operations in the neighboihood. The locality of the Fortres, " Old Point Comfort," enjoys such a high reputation for salubrity that it has bocomo ono of our moot famous seaboard summer resort8. Tho Hygeia Hotel, close under the guns of' the fortress, will doubtless be turned over to the accommodation of the outside federal troops. Tho surrounding waters literally swarm with fish, crabs and oysters-, so that the soldiers detailed to this military station will be in luck.