The author is not aware of any portion of his work that is open to controversy, unless it be that relating to a second visit to Ireland, asserted to have been made by the Earl of Glamorgan. However, should it be contended, or proved, that his negotiations refer to a _single_ visit there, the circumstance would not affect the main story. The author has, however, had one essential difficulty to deal with, arising from the quantity of correspondence and documentary evidence, which, under the circumstances, he was obliged to introduce, thus materially affecting the text. It certainly was open to him to throw the greater part into the Appendix, but with considerable drawbacks to all readers really interested in such a work. The course adopted has been to introduce documents, of whatever kind, in their order of date, and to modernise the orthography (and that alone) to render them generally readable. The few pieces admitted in their original style will satisfy any one how thoroughly unreadable the work would have become, if largely occupied with such orthography. The prayer (for example) is a strict copy of the original, which appears to be in the handwriting of the Marchioness, with several interlinear corrections made by the Marquis himself, which certify to its genuineness.[A] Every document is given with its own date, and no deviations occur beyond the modern spelling of words. The “Century,” however, being printed matter, has been re-produced verbatim, with scrupulous accuracy. The general reader will find that the really scientific portion of this memoir, is restricted to the “Century,” which has relieved the biographical portion of much technical detail: no more reference to inventions occurring therein than appeared absolutely necessary to preserve uniformity in the narrative. It was very desirable in such a work as the present to steer clear of a controversial strain, whether in reference to the past or the present. This has been effected in a great measure, as regards the numerous detractors that might be cited, who have given false views, both of the personal character of the Marquis, and the merit of some or most of his inventions, until we find the admiring biographer of the celebrated James Watt, as if blinded by too much light, speaking of the Marquis in the most disparaging terms. And lastly, it was impossible to escape recurring to the charge against Savery; the dates and facts, now for the first time supplied, going far to strengthen the belief, that the engine reputed to be Savery’s, is identical with that invented by the Marquis of Worcester.