It would appear that it had been long known to the members of the government, that a plan was in meditation by which they would all be murdered, and that Thistlewood was one of the originators of and prime movers in the horrid design; but in accordance with the system which then existed, of waiting until the crime should be all but matured, in order to secure a conviction of the offenders, they determined to make no effort to crush the scheme until a period should have arrived, when their own safety rendered it necessary. The conspirators meanwhile having weighed various plans and projects for the accomplishment of their object, eventually determined to select the evening of Wednesday the 23rd February as that on which they would carry out their plot, and it was deemed advisable that this night should be fixed upon, because it became known to them by an announcement in the newspapers, that a cabinet dinner would then be held at the house of Lord Harrowby in Grosvenor-square. Contemptible as the means possessed by the conspirators were to carry their design fully into execution, it is certain, from the confession of one of them, that the first part of their project was planned with so much circumstantial exactness, that the assassination of all the ministers would have been secured. It would appear that it was arranged, that one of the party should proceed to Lord Harrowby's house with a parcel addressed to his lordship, and that when the door opened, his companions should rush in, bind, or, in case of resistance, kill the servants, and occupy all the avenues of the house, while a select band proceeded to the chamber where the ministers were at dinner, and massacred the whole of them indiscriminately. To increase the confusion hand-grenades were prepared, which it was intended should be thrown lighted into the several rooms; and one of the party engaged to bring away the heads of lords Castlereagh and Sidmouth in a bag which he had provided for that purpose. Thus far the conspirators might probably have carried their plans into effect; but of the scheme for a general revolution, which these men, whose number never exceeded thirty, appear to have considered themselves capable of accomplishing, we cannot seriously speak. Among other arrangements the Mansion House, selected we suppose for its proximity to the Bank, was fixed upon for the "palace of the provisional government."