I request authority to send some extra laundresses to Fort Hamilton. They take up room on this island that is now needed for other purposes. Some of these laundresses were of the Eighth Infantry and some of the regiments and companies from California. Some of their husbands are in the field I believe on the Potomac.

Very respectfully, your obedient servant,

G. LOOMIS.

Colonel Fifth Infantry, Commanding.

[Inclosure.]

HEADQUARTERS, Fort Columbus, April 17, 1862.

We the undersigned having been granted the limits of the post (extending from the fort to the castle, thence around the west side of the island to the gardne and thence to the road leading back to the fort) do solemnly bind ourselves upon our honor that we will not take any advantage of the same; that we will not converse nor have any communication whatever with the sentinels or other soldiers of the post; that we will not attempt or connive at any attempt to communicate with the shore, and that between retreat and reveille we will not leave the quarters assigned to us; and further that we will commit no act nor utter any language militating against the Government of the United States.

C. M. AVERY,
Colonel Thirty-third Regiment North Carolina Troops.

[And 9 others.]

DETROIT, MICH., April 18, 1862.

ADJUTANT-GENERAL U. S. ARMY, Washington.

SIR: I have the honor to report that in compliance with the instructions of the Secretary of War I arrived at this place last evening on my way to Mackinac and find that the navigation of the upper lake is closed by ice and will probably remain so for a week or ten days. No prisoners of war have arrived at Detroit, and I am informed by Colonel Smith that the Governor of Michigan has refused to furnish a company of volunteers for their guard.

Fort Mackinac is a small work partly inclosed by small pickets and the buildings I believe were originally intended for only one company. It is now many years since I was stationed there but if my recollection is correct it does not seem more than a half acre of ground. I have no information in relation to the number of prisoners to be sent there, but I do not believe that the present buildings will afford even tolerable accommodation of rthe garrison and 200 men. If a greater number is to be quartered there buildings must be put up outside of the present site of the fort and the picketing extended so as to inclose them. This will of course involve considerable expense and require a larger force than one company to guard the prisoners.

It will require a great degree of vigilance on the part of the guard to keep 200 within the fort. The island of Mackinac is about nine miles in circumference with but few inhabitants except in the village of that name near the fort, and can be approached on all sides by boats. Among the mixed population of that island-a large number of whom are fishermen- and the persons who visit it I do not doubt that many could be found who for a small compensation would aid the prisoners to escape, hence the necessity of a strong guard. Drummond Island,