MONAGHAN, July 20.-- Trial for Conspiracy to murder Sir Harcourt Lees, Bart.-- Edward Slaven, Thomas Muckeius, and Patrick Marren, charged with a conspiracy to murder the Rev. Sir Harcourt Lees, Bart.

Sir Harcourt Lees sworn: Says he is rector of the parish of Killany; lives partly in the Glebe-house, mid-way between Ardee and Castleblaney; came last to reside there about the end of January last. Cross-examined by Mr. Scriven: Says Marren, the prisoner, has an excellent character.

John Milton, a soldier, sworn: Says he was in a public house in Carrick on the 17th of February last, and got three noggins of whiskey, and went out . Witness went in again on the evening of the same day; saw five persons there, who were talking in Irish afterwards they began talking In English. Knows the prisoners to be three of the five. Muckeius said Sir Harcourt was a d----d bad man , and sent a bad character of the Roman Catholics to Dublin; and said if he had him here he should not see morning. He, the prisoner, said likewise, that he would be d-----d but he would shoot Filgate and Sir Harcourt Lees, for they were not worthy to live.

Andrew McKittrick, landlord, sworn: Says when the last witness was in the house on that day, he was lying in a turf corner, quite incapable of hearing any discourse that was going on.

John Milton, the soldier, cross-examined by Mr. Scriven: Were you in this man's house on the 17th of February? -- I was. -- Did you see this man, McKittrick, in his house that day? -- No, Sir, I did not. -- Did you not see him in the room while you were lying on the turf? -- No, Sir, I did not; for it was the servant maid that brought in the three noggins that we warned. -- Not Guilty.-- Dublin Correspondent.

Weekly Intelligencer And British Luminary (London, England), August 6, 1820.