The following verbatim copy of a letter, in writing which is the hand-writing of JOHN WILKES BOOTH, the murderer of President LINCOLN, has been furnished us by the Hon. WM. MILLWARD, United States Marshal of the Eastern District of Pennsylvania. It was handed over to that officer by JOHN S. CLARKE, who is a brother-in-law of Mr. BOOTH. The history connected with it is somewhat peculiar. In November, 1864, the paper was deposited with Mr. CLARKE by BOOTH, in a sealed envelope, “for safe keeping,” Mr. CLARKE being ignorant of the contents. In January last BOOTH called at Mr. CLARKE’s house, asked for the package and it was given up to him. It is now supposed that at that time he took out the paper and added to it his signature, which appears to be in a different ink from that used in the body of the letter, and also from the language employed could not have been put to it originally. Afterward he returned the package to Mr. CLARKE again for safe keeping, sealed and bearing the superscription, “J. WILKES BOOTH.”

The inclosure was preserved by the family without suspicion of its nature. After the afflicting information of the assassination of the President, which came upon the family of Mr. CLARKE with crushing force, it was considered proper to open the envelope. There was found in it the following paper, with some 7-30 United States bonds, and a certificate of shares in oil companies. Mr. CLARKE promptly handed over the paper to Marshal MILLWARD, in whose custody it now remains. From a perusal of this paper it seems to have been prepared by BOOTH as a vindication of some desperate act which he had in contemplation; and, from the language used, it is probable that it was a plot to abduct the President and carry him off to Virginia. If this was meditated it failed, and from making a prisoner of the President to his assassination was an easy step for a man of perverted principles. It also appears that BOOTH was one of the party who was engaged in the capture and execution of JOHN BROWN, of Ossawattomie, at which time he doubtless imbibed from WISE and his associates those detestable sentiments of cruelty which have culminated in an infamous crime. The letter is

as follows: