The annexed Commentary has for its object to show the several sources from which it is not less probable than possible that the Marquis derived a certain amount of information for his guidance in endeavouring to advance and refine on the same by his own efforts at improvement. Many intelligent persons, particularly classical scholars, and men of purely literary tastes, whose reading has not embraced the study of the literature of science, have supposed that the whole or greater part of the Marquis of Worcester’s inventions emanated solely from his own unguided inventive skill; and not a few may have imagined it would be derogatory to the originality of an inventor to suppose him walking in the steps of others, however much he might outstrip their attainments in the same branch of inquiry. But all invention is progressive--first, laws of nature are discovered, then applications are invented, and last follow divisions and sub-divisions of endless great, small, and minute improvements. The Marquis originated many improvements, but assuredly only one pre-eminent invention, his great “fire water-work.” It would have been easy for us to make the commentary consist of essays on modern improvements, more or less traceable to the suggestive character of the “Century.” But we stop where the Marquis laid down his pen, preferring rather to show that materials existed from which he might derive the several classes of subjects therein noted, which many have so far doubted as to believe they originated wholly with himself; as by adopting the other course, we should only satisfy the public of the great use the “Century” has been to others, a matter which has never been doubted. We thus see that the “Century” is but the epitome of a greater work, designed to have been published with suitable explanatory engravings, which the premature decease of the author alone frustrated. During two hundred years the subjects of the various inventions and improvements it calendars have been long superseded, so that there is not one, perhaps, that would in the least assist the modern engineer, however minutely it could be described. Yet the history of the Steam Engine, of Inventions, and of Inventors would be incomplete indeed without a Memoir of the Marquis of Worcester, and some account of his inimitable “Century of Inventions.”