ADJUTANT-GENERAL'S OFFICE, Washington, April 16, 1861.

Organizations for the militia force called for by the President of the United States April 15, 1861:

A company of infantry--1 captain, 1 first lieutenant, 1 ensign, 4 sergeants, 4 corporals, 1 drummer and 1 fifes, 64 privates.

A company of foot riflemen--the same, except there may be bugler instead of the drummer and fifes; or about half the companies of a regiment or battalion may have a drummer and fifes, and the other companies a bugler.

A regiment of infantry or foot riflemen, to consist of ten companies--1 colonel, 1 lieutenant-colonel, 1 major, 1 adjutant, 1 regimental quartermaster, 1 surgeon, 1 assistant surgeon, 1 sergeant-major, 1 quartermaster-sergeant, 1 drum-major, 1 fife- major.

A brigade, to consist of two or more brigades-1 major-general, 2 aides-de-camp, 1 division inspector.

Some of the companies composing a regiment may be of infantry and the others rifle, if desired.

L. THOMAS,

Adjutant-General.

EXECUTIVE DEPARTMENT, Richmond, Va., April 16, 1861.

Honorable SIMON CAMERON,

Secretary of War:

SIR: I received your telegram of the 15th, the genuineness of which I doubted. Since that time I have received your communication, mailed the same day, in which I am requested to detach from the militia of the State of Virginia "the quota designated in a table" which you append, "to serve as infantry or riflemen for the period of three months, unless sooner discharged."

In reply to this communication I have only to say that the militia of Virginia will not be furnished to the powers at Washington for any such use or purpose as they have in view. Your object is to subjugate the Southern States, and requisition made upon me for such an object--an object, in my judgement, no within the purview of the Constitution or the act of 1795-will not be complied with. You have chosen to inaugurate civil war,and having done so, we will meet it in a spirit as determined as the Administration has exhibited toward the South.

Respectfully,

JOHN LETCHER.

HARRISONBURG, April 16, 1861.

General CAMERON,

Washington:

Could you not accept Ringgold Artillerists of Reading? They had already started and are very superior in men and drill.

ELI SLIFER,

Secretary Commonwealth.

[Indorsement.]

Reply: Yes.