HEADQUARTERS DEPARTMENT OF VIRGINIA, July 15, 1861.

Lieutenant-General SCOTT:

I have the honor to report that the term of enlistment of the Third and Fourth Massachusetts Regiments, three months' men, expires by limitation to morrow, and I have made arrangements to have them sent to Boston as the place of rendezvous. I had some doubt whether, as they were mustered into the service of the United States at Fort Monroe, that might not be considered their place of rendezvous; but learning from the colonels that they claimed their rendezvous at Boston, and as it would at best make but two or three days' difference in their term of service, and as there would be saved to the United States a very large amount of traveling fees over and above the cost of transportation, being, as near as I can reckon it, about twenty dollars per man, I have caused transportation and three days' rations to be furnished them, in order that they may be mustered out of service at Boston.

These two regimens were armed with the improved rifle muskets, while most of my regiments are armed with the issue of 1844, altered to percussion. Believing that these arms were distributed to the States under the act of Congress only to be used in the service of the Union, I have supposed that it was competent, as it was certainly desirable, to have them kept here, and therefore I have directed that all rifled muskets that will pass inspection of the ordnance officer at this post in the hands of the three-months' men be exchanged for the altered flint-lock muskets of 1844, and I propose to distribute these rifled muskets to the most deserving and best drilled troops. I also propose to have returned to my assistant quartermaster by the tree-months' men such tents and camp equipage as they have received from the United States, and allow them to take back with them such as has been furnished by the State of Massachusetts. I trust these dispositions will meet the approbation of the Commanding General.

It will be observed that by the return home of these men at least a thousand of the most effective of my troops are withdrawn from our forces, and I beg to call your attention to the fact that within fifteen days the First Vermont Regiment, three-months' men, 750 strong, being one of the best regiments here, will be entitled to a discharge. I would respectfully ask it the exigencies of the service will not permit other regiments, now being raised in Massachusetts or elsewhere, to be ordered here to take the place of those withdrawn by the expiration of enlistment.

I have further the honor to report that in a skirmish between Newport New and Warwick, by a patrolling party numbering one hundred and fifty, under the command of Colonel De Russy, late of the U. S. Army, Colonel De Russy and one other officer of captain, name unknown, were killed, and seven men wounded. No one was injured upon our side.

I have the honor to remain, your obedient servant,
BENJ. F. BUTLER,

Major-General, Commanding.