[Inclosure Numbers 4.]

U. S. STEAMER SAN JACINTO, At Sea, November 12, 1861.

Captain WILKES, Commanding San Jacinto.

SIR: In accordance with your instructions I submit the following:

On November 8, between 1 and 2 p. m., I was ordered by Lieutenant Breese, acting executive officer, to shove off with the third cutter and go alongside of the English mail steamer which was then lying to under our guns. In the boat with me were Third Assistant Engineer Hall, Paymaster's Clerk Simpson, Master's Mate Dahlgren, 1 sergeant, 1 corporal and 6 privates of marines, 4 machinists and the crew, consisting of 13 men, the whole party being well armed. When I arrived at the steamer I was met on the guard by Mr. Grace with a message from Lieutenant Fairfax (who had preceded me on board) to bring the marines on board adn station them outside of the cabin, which I did; also to keep the spare men on the guard and to have the boats' crews in readiness to jump on board if needed. As soon as the mariness were stationed I had the space outside and forward of the cabin kept clear of passengers and assumed a position where I could see Lieutenant Fairfax, who was then engaged in convention with persons in the cabin. He shortly came out and told me to remain as I was. He then went back into the cabin and in a few minutes returned with Mr. Mason. He had his hand on his shoulder and I think Mr. Hall had his on the other one. He transferred Mr. Mason to me and I had the third cutter houled up, into which he got. Shortly after Mr. Macfarland came out and got into the boat. I think he was unaccompanied by any of the officers.

About this time I heard a good deal of lond talking in the cabin and above all I heard a woman's voice. I could not hear what she said. Mr. Fairfax appeared to be having an altercation with some one. There was much confusion created by the passengers and ship's officers who were making all kinds of disagreeable and contemptuous noises and remarks.

Just then Mr. Houston came to me and said he thought there would be trouble. I told him to ack Mr. Fairfax if I should bring in the marines. He returned with an answer to bring them in. At that time I heard some one call out "Shoot him. " I ordered the marines to come into the cabin which they did at quick time. As they advanced the passengers fell back. Mr. Fairfax then ordered the marines to go out of the cabin which they did, Mr. Slidell at the same time jumping out of a window of the state-room into the cabin where he was arrested by Mr. Fairfax and was then brought by Mr. Hall and Mr. Grace to the boat, into which he got. Soon after Mr. Eustis came to the boat accompanied by Mr. Fairfax.

I then by his order took charge of the boat and conveyed the gentlemen arrested, viz, Messrs. Slidell, Mason, Macfarland and Eustis, to the San Jacinto where I delivered them over to Captain Wilkes. This was about 2 o'clock. I then returned to the steamer. When I reached her the baggage of the gentlemen was being brought up the sent to the San Jacinto. Soon after Mr. Fairfax told me to send the marines and spare hands on board which I did. He then left me in charge of our party and went on board the San Jacinto. About 3 o'clock she ran under the Trent's stern. I was hailed and directed to come on board, which I did with all exceting Mr. Grace, Mr. Dahlgren and Mr. Hall, who came in another boat.

Very respectfully, your obedient servant,

JAMES A. GREER,

Lieutenant.