His Lordship’s invention was never offered by him as a merely amusing trifle; it was not a curious model which might or might not possess some practical advantage; and it was not of a nature of which he was but partially aware, and which it was left to others to apply. It is even possible that as early as 1628 he had set up his Engine in its most simple form of application; and that, improved upon through thirty-five years of study and experimenting, the Engine of 1663 was a master-piece of workmanship and contrivance for that age. His invention was no longer a secret, he had done all that any inventor could possibly be required to perform to establish his claim to be considered as a true and first inventor. His right did not depend on the vague notice first put forth in his _Century_, but on the actual Engine made, and, for not less than seven years, constantly worked for public inspection at Vauxhall. Any one so disposed could have obtained the same examination of it that was conceded to Sorbière and to Cosmo de Medici. Dr. Hook does not condescend to state what he saw of it; he set out for Lambeth with the intention of going to Vauxhall, but the _laughing_ philosopher may have settled the problem in his own mind, to his own entire satisfaction, without taking any trouble on a supposed foolish errand. We speculate in vain whether among the visitors stimulated by curiosity, or invited by intending shareholders, there were such men as Sir Samuel Morland, the King’s Master of Mechanics; Rupert, Duke of Cumberland; Dr. Sprat, the historian of the Royal Society; Bishop Wilkins, the author of “Mathematical Magic”; the Honourable Robert Boyle, Sir William Petty, Lord Viscount Brouncker, and other distinguished personages.