On the morning of the 22d of May last, Major-General Butler, welcomed with a military salute, arrived at Fortress Monroe, and assumed the command of the Department of Virginia. Hitherto we had been hemmed up in the peninsula of which the fort occupies the main part, and cut off from communication with the surrounding country. Until within a few days our forces consisted of about one thousand men belonging to the Third and Fourth Regiments of Massachusetts militia, and three hundred regulars. The only movement since our arrival on the 20th of April had been the expedition to Norfolk of the Third Regiment, in which it was my privilege to serve as a private. The fort communicates with the main-land by a dike or causeway about half a mile long, and a wooden bridge, perhaps three hundred feet long, and then there spreads out a tract of country, well wooded and dotted over with farms. Passing from this bridge for a distance of two miles northwestward, you reach a creek or arm of the bay spanned by another wooden bridge, and crossing it you are at once in the ancient village of Hampton, having a population of some fifteen hundred inhabitants. The peninsula on which the fort stands, the causeway, and the first bridge described, are the property of the United States. Nevertheless, a small picket-guard of the Secessionists had been accustomed to occupy a part of the bridge, sometimes coming even to the centre, and a Secession flag waved in sight of the fort. On the 13th of May, the Rebel picket-guard was driven from the bridge, and all the Government property was taken possession of by a detachment of two companies from the Fourth Regiment, accompanied by a dozen regulars with a field-piece, acting under the orders of Colonel Dimick, the commander of the post. They retired, denouncing vengeance on Massachusetts troops for the invasion of Virginia. Our pickets then occupied the entire bridge and a small strip of the main-land beyond, covering a valuable well; but still there was no occupation in force of any but Government property. The creation of a new military department, to the command of which a major-general was assigned, was soon to terminate this isolation. On the 13th of May the First Vermont Regiment arrived, on the 24th the Second New York, and two weeks later our forces numbered nearly ten thousand.

On the 23d of May General Butler ordered the first reconnoitring expedition, which consisted of a part of the Vermont Regiment, and proceeded under the command of Colonel Phelps over the dike and bridge towards Hampton. They were anticipated, and when in sight of the second bridge saw that it had been set on fire, and, hastening forward, extinguished the flames. The detachment then marched into the village. A parley was held with a Secession officer, who represented that the men in arms in Hampton were only a domestic police. Meanwhile the white inhabitants, particularly the women, had generally disappeared. The negroes gathered around our men, and their evident exhilaration was particularly noted, some of them saying, "Glad to see you, Massa," and betraying the fact, that, on the approach of the detachment, a field-piece stationed at the bridge had been thrown into the sea. This was the first communication between our army and the negroes in this department.

The reconnoissance of the day had more important results than were anticipated. Three negroes, owned by Colonel Mallory, a lawyer of Hampton and a Rebel officer, taking advantage of the terror prevailing among the white inhabitants, escaped from their master, skulked during the afternoon, and in the night came to our pickets. The next morning, May 24th, they were brought to General Butler, and there, for the first time, stood the Major-General and the fugitive slave face to face. Being carefully interrogated, it appeared that they were field-hands, the slaves of an officer in the Rebel service, who purposed taking them to Carolina to be employed in military operations there. Two of them had wives in Hampton, one a free colored woman, and they had several children in the neighborhood. Here was a new question, and a grave one, on which the Government had as yet developed no policy. In the absence of precedents or instructions, an analogy drawn from international law was applied. Under that law, contraband goods, which are directly auxiliary to military operations, cannot in time of war be imported by neutrals into an enemy's country, and may be seized as lawful prize when the attempt is made so to import them. It will be seen, that, accurately speaking, the term applies exclusively to the relation between a belligerent and a neutral, and not to the relation between belligerents. Under the strict law of nations, all the property of an enemy may be seized. Under the Common Law, the property of traitors is forfeit. The humaner usage of modern times favors the waiving of these strict rights, but allows,—without question, the seizure and confiscation of all such goods as are immediately auxiliary to military purposes. These able-bodied negroes, held as slaves, were to be employed to build breastworks, to transport or store provisions, to serve as cooks or waiters, and even to bear arms. Regarded as property, according to their master's claim, they could be efficiently used by the Rebels for the purposes of the Rebellion, and most efficiently by the Government in suppressing it. Regarded as persons, they had escaped from communities where a triumphant rebellion had trampled on the laws, and only the rights of human nature remained, and they now asked the protection of the Government, to which, in prevailing treason, they were still loyal, and which they were ready to serve as best they could.

The three negroes, being held contraband of war, were at once set to work to aid the masons in constructing a new bakehouse within the fort. Thenceforward the term "contraband" bore a new signification, with which it will pass into history, designating the negroes who had been held as slaves, now adopted under the protection of the Government. It was used in official communications at the fort. It was applied familiarly to the negroes, who stared somewhat, inquiring, "What d' ye call us that for?" Not having Wheaton's "Elements" at hand, we did not attempt an explanation. The contraband notion was adopted by Congress in the Act of July 6th, which confiscates slaves used in aiding the Insurrection. There is often great virtue in such technical phrases in shaping public opinion. They commend practical action to a class of minds little developed in the direction of the sentiments, which would be repelled by formulas of a broader and nobler import. The venerable gentleman, who wears gold spectacles and reads a conservative daily, prefers confiscation to emancipation. He is reluctant to have slaves declared freemen, but has no objection to their being declared contrabands. His whole nature rises in insurrection when Beecher preaches in a sermon that a thing ought to be done because it is a duty, but he yields gracefully when Butler issues an order commanding it to be done because it is a military necessity.

On the next day, Major John B. Cary, another Rebel officer, late principal of an academy in Hampton, a delegate to the Charleston Convention, and a seceder with General Butler from the Convention at Baltimore, came to the fort with a flag of truce, and, claiming to act as the representative of Colonel Mallory, demanded the fugitives. He reminded General Butler of his obligations under the Federal Constitution, under which he claimed to act. The ready reply was, that the Fugitive-Slave Act could not be invoked for the reclamation of fugitives from a foreign State, which Virginia claimed to be, and she must count it among the infelicities of her position, if so far at least she was taken at her word.

The three pioneer negroes were not long to be isolated from their race. There was no known channel of communication between them and their old comrades, and yet those comrades knew, or believed with the certainty of knowledge, how they had been received. If inquired of whether more were coming, their reply was, that, if they were not sent back, others would understand that they were among friends, and more would come the next day. Such is the mysterious spiritual telegraph which runs through the slave population. Proclaim an edict of emancipation in the hearing of a single slave on the Potomac, and in a few days it will be known by his brethren on the Gulf. So, on the night of the Big Bethel affair, a squad of negroes, meeting our soldiers, inquired anxiously the way to "the freedom fort."

The means of communicating with the fort from the open country became more easy, when, on the 24th of May, (the same day on which the first movement was made from Washington into Virginia,) the Second New York Regiment made its encampment on the Segar farm, lying near the bridge which connected the fort with the main-land, an encampment soon enlarged by the First Vermont and other New York regiments. On Sunday morning, May 26th, eight negroes stood before the quarters of General Butler, waiting for an audience.

They were examined in part by the Hon. Mr. Ashley, M.C. from Ohio, then a visitor at the fort. On May 27th, forty-seven negroes of both sexes and all ages, from three months to eighty-five years, among whom were half a dozen entire families, came in one squad. Another lot of a dozen good field-hands arrived the same day; and then they continued to come by twenties, thirties, and forties. They were assigned buildings outside of the fort or tents within. They were set to work as servants to officers, or to store provisions landed from vessels,—thus relieving us of the fatigue duty which we had previously done, except that of dragging and mounting columbiads on the ramparts of the fort, a service which some very warm days have impressed on my memory.

On the 27th of May, the Fourth Massachusetts Regiment, the First Vermont, and some New York regiments made an advance movement and occupied Newport News, (a promontory named for Captain Christopher Newport, the early explorer,) so as more effectually to enforce the blockade of James River. There, too, negroes came in, who were employed as servants to the officers. One of them, when we left the fort, more fortunate than his comrades, and aided by a benevolent captain, eluded the vigilance of the Provost Marshal, and is now the curiosity of a village in the neighborhood of Boston.

It was now time to call upon the Government for a policy in dealing with slave society thus disrupted and disorganized. Elsewhere, even under the shadow of the Capitol, the action of military officers had been irregular, and in some cases in palpable violation of personal rights. An order of General McDowell excluded all slaves from the lines. Sometimes officers assumed to decide the question whether a negro was a slave, and deliver him to a claimant, when, certainly in the absence of martial law, they had no authority in the premises, under the Act of Congress,—that power being confided to commissioners and marshals. As well might a member of Congress or a State sheriff usurp the function. Worse yet, in defiance of the Common Law, they made color a presumptive proof of bondage. In one case a free negro was delivered to a claimant under this process, more summary than any which the Fugitive-Slave Act provides. The colonel of a Massachusetts regiment showed some practical humor in dealing with a pertinacious claimant who asserted title to a negro found within his lines, and had brought a policeman along with him to aid in enforcing it. The shrewd colonel, (a Democrat he is,) retaining the policeman, put both the claimant and claimed outside of the lines together to try their fleetness. The negro proved to be the better gymnast and was heard of no more. This capricious treatment of the subject was fraught with serious difficulties as well as personal injuries, and it needed to be displaced by an authorized system.