The Severall Tryals of Sir Henry Slingsby Kt. John Hewet D.D. and John Mordant Esq; for High Treason in Westminster Hall. Together with the Lord President's Speech Before the Sentence of Death was Pronounced Against the Aforenamed Sir H. Slingsby and Dr. Hewett, Being the 2. of June, 1658. At which Time the Said Mr. Mordant was by the Court Acquitted. As Also the Manner of Their Execution on Tower-Hill, the 8. of June Following, with the Substance of Their Speeches on the Scaffold