Embracing communications, etc., received too late for insertion in proper sequence.

HEADQUARTERS ARMY OF THE POTOMAC,
In Camp at Harrison's Landing, James River,

Thursday, August 6, 1862.

Honorable WM. H. SEWARD,

Secretary of State, Washington, D. C.:

DEAR SIR: I am satisfied, from information received here, that the rebel gunboat fleet will not be out for a well or two yet at least, and that there will be able time to prepare for its reception in the manner that I have heretofore proposed.*

I am afraid, from information and indications received here, that it is the plan of the rebels, relying on the weakness and the slowness of McClellan's army, to outnumber and out general Pope, and make a desperate dash upon Washington. I am fully convinced that this is part of their present policy. Consequently I beg leave to again urge upon the administration that Pope ought to be put on his guard and re-enforced to the greatest possible extent, while McClellan ought to be instructed to keep a constant and very heavy pressure upon the rebel army at Richmond, to prevent it from re-enforcing Jackson. Malvern Hill has been taken and lost, but the pressure should be kept up.

I beseech the administration to think and act upon the above suggestions, before it is too late, and another terrible panic is sprung upon Washington, which if not nits actual may in its moral effect prove disastrous to the cause of the Union. The rebel Government is aware of the call for 600,000 men, and they know that now is their time to strike, and you may rest assured they will do it. It becomes us to make the very best disposition of our discipline forces already in the field, so as to anticipate and thwart the desperate strike that the rebels are no doubt about to make, with the impression that we are inactively waiting for the 600,000 new recruits.

Ever truly, your friend and obedient servant,

T. S. S. [SEYBOLT.]

[Indorsement.]

(Received Headquarters Army, August 11, 1862.)

Major-General HALLECK:

MY DEAR GENERAL: I am informed that I may depend on Mr. Seybolt's information as to facts. As to his speculations, they, like everybody elese's speculations, must be judged by their merits.

Very truly, yours,

WILLIAM H. SEWARD.

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*See Series I, Vol. XI, Part III, pp. 334-336.

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