WASHINGTON, July 27, 1863.

(Received 10. 20 a. m.)

General R. INGALLS,

Headquarters Army of the Potomac:

Another attempt was made to throw off and capture our trains near Burke's yesterday. Rails were taken out and horseshoes placed on track. Fortunately, the rails were taken up on the inside instead of the outside of the curve, and the train was not thrown off. Twelve rebels, in gray and blue costumes, armed with guns, made their appearance, and were chased by the train guard, but none captured.

These attempts to throw off trains are made daily, and unless the practice can be broken up, there is no security in your communications. To operate the road with reasonable security, we must have the gaps of the Blue Ridge so occupied that Lee's cavalry cannot get through, the fords of the Occoquan guarded, the country patrolled by cavalry, and notice given the inhabitants that, in case of any further attempts to disturb track or telegraph, all able-bodied residents within a circle of 10 miles will be arrested and placed under guard.

Please communicate with General Meade, and have an order issued giving notice to the inhabitants, something to this effect:

Notice is hereby given that if any attempt shall be made to destroy the track, bridges, or telegraph on any of the lines of railroad used by the Army of the Potomac, the residents in the vicinity, for a distance of 10 miles, will be held responsible in person and property, and all able-bodied citizens arrested. If the offenders can be discovered, their punishment will be death.

I will endeavor to see you to-morrow. Would it be will to search houses and seize arms? This I know is an extreme measure, but I am confident that those who appear to be farmers during the day are the parties who injure us at night.

H. HAUPT.

HEADQUARTERS DEPARTMENT OF THE SUSQUEHANNA,
July 27, 1863.

Brigadier General WILLIAM F. SMITH, Hagerstown:

SIR: Your note of yesterday id received, &c. The emergency men are being ordered to Harrisburg, to be mustered out.

I am going to send two or three regiments of militia to Reading, to increase the force there. A good deal of difficulty is apprehended in the coal regions; but if we get through with Philadelphia with no outbreak, it is hoped that the balance of the State will be quiet.

I am to order to Harrisburg the militia regiments, to be mustered out of service, as the Governor makes requisition upon me ; and as Franklin's men are among the oldest in service, his men will, in all probability, be among the first to go out.

As regards sending drafted men to you, I fancy that they are to fill up old regiments in the field.

I regards sending drafted men to you, I fancy that they are to fill up old regiments in the field.

I regret that you have been under the weather, and hope you may speedily be yourself again.

Morgan and his command were captured yesterday at 2 p. m. Duer has gotten an extension of leave.

Respectfully, your obedient servant,

D. N. COUCH,

Major-General.