As in the case of his removal to Exiles, so, upon the present occasion, St. Mars went first to look at and prepare the prison at St. Margaret, before he conveyed his prisoner there.[124] Previously, however, to leaving him for that purpose, he writes to Louvois, to assure him once more of the secrecy and security with which he is confined--“I have given such good orders for the guarding of my prisoner, that I can answer for his entire security; as well as for his not now, nor ever, holding any intercourse with my Lieutenant, whom I have forbidden to speak to him, which is punctually obeyed.”[125] He afterwards writes again to the same Minister, from the Island of St. Margaret, “I promise to conduct my prisoner here in all security, without any one’s seeing or speaking to him. He shall not hear mass after he leaves Exiles, till he is lodged in the prison which is preparing for him here, to which a chapel is attached. I pledge my honour to you for the entire security of my prisoner.”[126] St. Mars accordingly returned for Matthioli, and conveyed him to his new abode, in the manner he had proposed doing, in his letter to Louvois, of January 20th, 1687--“In a chair, covered with oil-cloth, into which there would enter a sufficiency of air, without its being possible for any one to see or speak to him during the journey, not even the soldiers, whom I shall select to be near the chair.”[127] In spite of the expectations of St. Mars that, in this mode of conveyance, his prisoner would have air enough, it appears that he complained of the want of it, and soon fell ill in consequence. This is mentioned in a letter of St. Mars, dated May 3d, 1687, giving an account of their arrival at the Island of St. Margaret, and is the last of the correspondence between Louvois and St. Mars respecting Matthioli: “I arrived here the 30th of last month. I was only twelve days on the journey, in consequence of the illness of my prisoner, occasioned, as he said, by not having as much air as he wished. I can assure you that no one has seen him, and that the manner in which I have guarded and conducted him during all the journey, makes every body try to conjecture who my prisoner is.”[128] It was probably, during this journey, that St. Mars first made use of a mask to hide the features of Matthioli.[129] Not as has been erroneously supposed a mask made of iron, which it will be evident, upon the slightest reflection, could not have been borne upon the face for any long continuance of time, but one of black velvet,[130] strengthened with whalebone, and fastened behind the head with a padlock, which did not prevent the prisoner from eating and drinking, or impede his respiration.[131]