SAINT LOUIS, MO., June 5, 1861.

Bvt. Brigadier General L. THOMAS,

Adjutant-General, U. S. Army, Washington, D. C.:

GENERAL: I have the honor to acknowledge the receipt of your letter of the 27th ultimo, containing instructions to put down all attempts to commit outrages on loyal citizens of Missouri.

In reply to that letter I respectfully refer you to my communication of the 29th ultimo, written and mailed before the receipt of yours. I therein informed the Government that I had reliable means of obtaining information of the movements of the State authorities, and that I should promptly punish any violation of agreement and put down any attempt at rebellion. The many complaints of individuals, by letter, setting forth that acts of oppression were committed by the secessionists, have received my careful attention, and an investigation has proved the majority of them to be without foundation. As an instance of the groundlessness of these mischievous rumors I cite the report, which obtained currency, that Ex-Governor Stewart and other loyal citizens had been driven from Saint Joseph, and the ex-governor promptly publishing an unqualified denial that such outrage was perpetrated, clearly proves that there is a disposition on the part of some parties to manufacture excitement where cause does not exist.

My confidence in the honor and integrity of General Price, in the purity of his motives, and in his loyalty to the Government, remains unimpaired. His course as president of the State Convention that voted by a large majority against submitting an ordinance of secession, and his efforts since that time to calm the elements of discord, have served to confirm the high opinion of him I have for many years entertained.

My whole course as commander of the Department of the West has been dictated by a desire to carry out in good faith the instructions of my Government, regardless of the clamor of the conflicting elements surrounding me, and whose advice and dictation could not be followed without involving the State in blood and the Government in the unnecessary expenditure of millions. Under the course I pursued Missouri was secured to the Union, and the triumph of the Government was only the more glorious, being almost a bloodless victory; but those who clamored for blood have not ceased to impugn my motives. Twice within a brief space of time have I been relieved from the command here; the second time in a manner that has inflicted unmerited disgrace upon a true and loyal soldier. During a long life, dedicated to my country, I have seen some service, and more than once I have held her honor in my hands; and during that time my loyalty, I believe, was never questioned; and now, when in the natural course of things I shall, before the lapse of many years, lay aside the sword which has so long served my country, my countrymen will be slow to believe that I have chosen this portion of my career to dame with treason my life, which is so soon to become a record of the past, and which I shall most willingly leave to the unbiased judgment of posterity. I trust that I may yet be spared to do my country some further service that will testify to the love I bear her, and that the vigor of my arm may never relax while there is a blow to be struck in her defense.

I respectfully ask to be assigned to the command of the Department of California, and I doubt not the present commander of that division is even now anxious to serve on the Atlantic frontier.

I am, sir, very respectfully, your obedient servant,

WM. S. HARNEY,

Brigadier-General, U. S. Army.