BOSTON, July 28, 1862.

General L. THOMAS, Adjutant-General:

Prisoners of war leave Thursday morning. Shall send Flag-Officer Barron, Commander Mitchell and all Navy prisoners. Shall send also two lieutenants of the Navy, De Bree and Glassell, unless otherwise ordered. Some eight or nine prisoners say they will be hung if they go South. Some have taken the oath of allegiance. Fufther orders.

J. DIMICK,

Colonel, Commanding.

COLUMBUS, OHIO, July 28, 1862.

Colonel WILLIAM HOFFMAN,

Third Infantry, U. S. Army, Commissary-General of Prisoners.

COLONEL: I have the honor to submit to you the following report upon the condition of matters connected with the prison camp of Camp Chase at this place upon my arrival here and at the present time:

I am glad to be able to inform you that the written instructions contained in my letter to the commanding officer here directing certain improvements in the prisons and other departments connected with them, and which have already been submitted to your approval in a previous report, have in most cases been put in force by the commanding officer, and this too previous to my arrival. As a consequence a marked change is observed in the health, cleanliness, police and comfort of the prisoners and decidedly for the better. The quartermaster has already completed a very complete grading of all of the prisons thereby securing a complete drainage. They will soon be provided with complete privies, those in prison Numbers 3 being finished and the others in a fair way toward fitting them for use. The quarters are nearly all thoroughly whitewashed, and this together with the free use of line in connection with the changes referred to render the atmosphere of the prisons comparatively pure.

The prisoners in Numbers 3 do all of their cooking by the six Farmer's boilers and twelve stoves, two to each mess, to enable them to bake their corn-meal and prepare in various ways a few small articles of the ration. The method adopted by them is that generally followed in the Army of boiling their rations and making soup. Fresh beef is issued five times a week. I have directed that rice or beans shall be issued daily to the prisoners, one in lieu of the other when hominy is not issued; when, however, hominy is issued neither beans nor rice for that day, the object being to give them one and only one of these articles of food at the same time, or forming a part of the same ration. This is somewhat less than the allowance at present given under the recent commissary regulation to exist during this war, there being allowed under it a full ration of either two, as beans and rice, beans and hominy, rice and hominy. But I believe that it was more than enough for men taking little or no exercise, and more particularly as of most of the food a considerable portion daily finding its was to the slop tubs. I have directed that hominy be issued in the proportion of two-sevenths and beans or rice five-sevenths, and corn-meal inplace of bread or flour five times per week. The prisoners are quite successful in the use of the boilers, and there is no doubt but that their cost would soon be replaced by the immense saving of fuel over stoves. The use of milk by the prisoners has been allowed by permitting the suttlers to seel it.

The camps are thoroughly policed twice each day (or rather the prisons) in the manner detailed to be done in my first report to you.