A letter from St. Omars, in farther confirmation of the truth of the Popish Plot, upon a consideration of divers circumstances in the trials. : Together with several new matters relating to a farther discovery thereof; and particularly, a letter from Mr. Jennison, proving Mr. Ireland to have been in London the 19th. of August, contrary to the Staffordshire witnesses, and what the five Jesuits (lately executed) insisted upon at their trials. With remarks upon the said letter.