COLONEL: I found, on my return to this place from a reconnoissance of a portion of the valleys of San Joaquin and Sacramento Rivers, general orders No. 1 from the headquarters of the army; and, as I cannot have copied in season for transmission by the steamer of the 1st proximo the military correspondence at these headquarters, I respectfully submit, for the information of the commander-in-chief, a brief summary of reports heretofore made in relation to military affairs in this department. My attention was directed, on my arrival in this country, to the unparalleled excitement in relation to the mineral regions; the imminent danger that our troops, as they arrived, would desert to the "_placers_," and, instead of giving protection to the parties, and aid in the preservation of order and tranquillity, would themselves become the very worst element of disorder; the great extent of Indian frontier to be guarded, and the difficulties then apprehended from the unsettled state of affairs in the mining districts. An attentive consideration of these subjects impressed me with the opinion that the policy most likely to prove advantageous to the service, would be the concentration of all the troops serving in this department, except the necessary guards for the depots at one or more points in the immediate vicinity of the gold regions, from whence a portion of them might be permitted to visit the placers for the purpose of working them for their own benefit--the remainder to be held embodied in a proper state of discipline, in readiness for any emergency that might occur. After the expiration of the furlough of the first class, a second class to be furloughed, and so in succession with the remainder; the troops stationed at points so distant from the mines, that they could not be furloughed, to be relieved by exchange with commands that have been more favorably situated. The practice of granting furloughs, adopted at some of the posts in this country, with the sanction of the former department commander, had succeeded well, and the information received about the time of my arrival from the southern part of this department confirmed me in the opinion previously entertained, that the mania for gold-hunting would exist, in its most exaggerated form, at points most remote from the _placers_. I accordingly, immediately after relieving Colonel Mason in the command of the department, recommended the adoption of the policy above indicated. It is a matter of regret, that the emergencies of the service have been such that it could not be carried out to the extent recommended; for the experience of the past four months has convinced me that it is the only course that can be adopted, with reasonable hope of success, until the state of affairs in this country is materially changed. In addition to the mere question of expediency, Indian difficulties that were then occurring, and the threatening danger of a proximate collision between the