In conclusion, I beg leave to say that as soon as I know the wishes of the General-in-Chief I will carry them out with alacrity. And should it be decided to withdraw a portion of the present force I will do the best I can with what remains.

We have transportation available for 3,000 men to go by sea.

I have the honor to be, very respectfully, your obedient servant,

J. G. FOSTER,

Major-General, Commanding.

WASHINGTON, D. C., June 21, 1864.

Major-General FOSTER,

Department of the South:

GENERAL: Your letter of the 16th instant, transmitting the correspondence between yourself and the commanding general of the rebel forces at Charleston in regard to confining our officers prisoners of war, in the part of that city exposed to the fire of our batteries, is just received. The Secretary of War has directed an equal number of rebel generals and field officers be sent to you by Major Strong, to be treated in precisely the same manner as the enemy treat ours - that is, to be placed in positions where they will be not exposed to the fire of the rebels. In whatever position they may be placed, whether in the field or in our batteries or vessels, you will take proper precautions to prevent their escape or recapture, putting them in irons, of necessary, for that purpose. The Secretary of War directs that on this point you will exercise great vigilance and that the rebel officers will be treated with the same severity that they treat ours.

Very respectfully, your obedient servant,

H. W. HALLECK,

Major-General, Chief of Staff.

OFFICE WEST POINT FOUNDRY,

30 Broadway, New York, June 21, 1864.

Major General J. G. FOSTER:

MY DEAR SIR: Though I suppose most of the points of importance in regard to the service of my guns are by this time understood, there are one or two that are of such exceeding interest that I am induced to mention them. The greatest difficulty now to be encountered is in the premature explosion of shells in the bore of the gun. The charge of powder they will hold is quite large, and owing to the elongated form of the projectile or to its being driven into the groves, there seems to be a tendency of the parts of the broken shell to wedge in the bore, thus carrying away muzzle or some other part, or, at any rate, giving the gun a violent strain which is afterward and perhaps by other accidents developed into the destruction of the gun. As a means of diminishing this danger, I am now lacquering or varnishing the interior surface of the shells. Even when freshly put in it operates favorably. A little poured in at the fuse hole and then caused to run over the sides by laying the shells down and rolling it will answer.

The reason for this seems to be that on firing the gun the powder charge of the shells is violently thrown back, and explosion is