A few hundred more will be gathered from the trains at this depot. Two hundred and fifty arrived last night, and will be forwarded as soon as shod and fed, and rested for twenty-four hours from their journey. Three hundred start from Detroit to-day and to-morrow; 275 from Boston, by special train, last night.

I think you will be refitted as fast as you can distribute the horses and the necessary equipments.

Captains Blood and Smith have orders to forward to headquarters all equipments, horses, wagons, and property which may be service-able and desired at headquarters. Other property is to be sent to this depot.

M. C. MEIGS,

Quartermaster-General.

[P. S.]-The canal is navigable, and a party goes up to-day to complete repair of lock-gates where needed.

QUARTERMASTER-GENERAL'S OFFICE, July 6, 1863-5 p. m.

Brigadier General R. INGALLS,

Chief Quartermaster, Army of the Potomac:

GENERAL: Your dispatch of this date just received. Including remounted cavalry, but excluding artillery, batteries, wagons with teams, and cavalry not lately remounted, I estimate that to-morrow morning there will be about 5, 000 fresh horses on their way to you at Frederick. These come from this place, Boston, New York, Philadelphia, Baltimore, Harrisburg, Indianapolis, Detroit, and about 170 will start to-morrow from Chicago. All, if fortunate, will arrive in a very few days. The superintendents of all railroads over which they pass have been telegraphed, and urged to aid in their most rapid transit. These are all already purchased, and the property of the Government, held in reserve at various points for this occasion.

M. C. MEIGS,

Quartermaster-General.

WASHINGTON, D. C., July 6, 1863-9. 30 p. m.

Brigadier General R. INGALLS,

Chief Quartermaster, Army of the Potomac, Frederick, Md.:

Your dispatch of yesterday was received this morning.

I have ordered 750, 000 pounds of grain and 250, 000 pounds of hay to be sent, daily, to Frederick. If this not sufficient, notify me, and more will be sent.

I have ordered 25, 000 pairs of bootees and 25, 000 pairs of stockings, with a supply of horseshoes, nails, &c., to the same point. They go forward to-night.

I have collected 800 cavalry horses, in addition to the 1, 600 already sent, which I will send to-morrow if I can get the cars. I would send them by the turnpike if I could possibly raise the men to take charge of them. I think, however, I shall be able to get them off in the cars to-morrow.

D. H. RUCKER,

Brigadier-General, and Quartermaster.