trains of cars, one of which, consisting of a locomotive and seven cars, has been already secured and brought into Jacksonville. The rebels had taken away one or two important pieces of the locomotive, which can soon be replaced.

Upon the report of this successful operation I resolved immediately to re-enforce General Birney with five regiments, and to have him move out with his whole force, and make a sweep of all horses and cattle and all able-bodied negro men from the Santa Fe and New Rivers, southward over the counties of Alachua, Levy, and Marion, and to bring his spoils across the upper Saint John's safely into he territory east of that river. If opportunity offered by the continued weakness of the enemy in Florida, he was to drive the enemy beyond the Suwannee River and destroy as much of the Central Railroad as possible. The Florida Railroad from Fernandina to Cedar Keys was to be kept intact to favor our own operations.

The troops were already embarking for this purpose when your order of he 25th ultimo, inclosing telegraphic order* from General Grant, was received. Although this order was not peremptory, I did not consider that our necessities would warrant my delaying to carry out its directions at once. I therefore sent orders to General Birney to proceed at once to Fort Monroe with his brigade. Brigadier General J. P. Hatch was immediately ordered from here to proceed at once to take command in General Birney's place, with regiments from this place to replace those taken away by General Birney, increased by an additional force from this vicinity, to enable him if possible to carry out the programme laid down for General Birney's action. Brigadier-General Hatch sailed with his force day before yesterday (the 2nd instant).

General Birney, with that portion of his brigade now in Florida, had not yet arrived. One of the regiments of his brigade now here is sent on the Fulton, which sails this p. m., and the remaining ones will follow in transportation already provided immediately on their arrival from Florida. These four regiments number 2,500 effectives, and although colored troops, are as good as any troops in this department.

The health of the department is as good as it usually is at this season of the year, but many officers and men are beginning to feel the effects of the heat and their efficiency is correspondingly impaired.

The operations in the North District have been satisfactory. The slow and careful firing upon Fort Sumter is beginning to exhibit a marked effect; two breaches, one on the gorge and the other on the right flank, are being successfully made. this immense mass of debris that is presented in appearance to our forts is being smashed up and blown away by our shells in a slow but a sure manner. In a reasonable time the fort will be rendered untenable, and if still held by the enemy can be taken by our troops at any time we choose. I prefer, however, before doing his to wait until the preparations are completed, so as to avoid loss of life.

I have the honor to be, general, very respectfully, your obedient servant,

J. G. FOSTER,

Major-General.

Major General H. W. HALLECK,

Chief of Staff.