[30] Sir Giles Overreach, in the play of "A new way to pay old debts," by Philip Massinger. It was difficult for the poet, or any other person, to libel such a personage as Mompesson. [31] Pett's method is described in a paper contained in the S.P.O., dated 21st Oct., 1626. The Trinity Corporation adopted his method. [32] Memoirs of the Life and Services of Rear-Admiral Sir William Symonds, Kt., p. 94. [33] Pett's dwelling-house at Rochester is thus described in an anonymous history of that town (p. 337, ed. 1817):--"Beyond the Victualling Office, on the same side of the High Street, at Rochester, is an old mansion, now occupied by a Mr. Morson, an attorney, which formerly belonged to the Petts, the celebrated ship-builders. The chimney-piece in the principal room is of wood, curiously carved, the upper part being divided into compartments by caryatydes. The central compartment contains the family arms, viz., Or, on a fesse, gu., between three pellets, a lion passant gardant of the field. On the back of the grate is a cast of Neptune, standing erect in his car, with Triton blowing conches, &c., and the date 1650." [34] Symonds, Memoirs of Life and Services, 94. CHAPTER II. FRANCIS PETTIT SMITH: PRACTICAL INTRODUCER OF THE SCREW PROPELLER. "The spirit of Paley's maxim that 'he alone discovers who proves,' is applicable to the history of inventions and discoveries; for certainly he alone invents to any good purpose, who satisfies the world that the means he may have devised have been found competent to the end proposed."--Dr. Samuel Brown. "Too often the real worker and discoverer remains unknown, and an invention, beautiful but useless in one age or country, can be applied only in a remote generation, or in a distant land. Mankind hangs together from generation to generation; easy labour is but inherited skill; great discoveries and inventions are worked up to by the efforts of myriads ere the goal is reached."--H. M. Hyndman. Though a long period elapsed between the times of Phineas Pett and "Screw" Smith, comparatively little improvement had been effected in the art of shipbuilding. The Sovereign of the Seas had not been excelled by any ship of war built down to the end of last century.[1] At a comparatively recent date, ships continued to be built of timber and plank, and impelled by sails and oars, as they had been for thousands of years before. But this century has witnessed many marvellous changes. A new material of construction has been introduced into shipbuilding, with entirely new methods of propulsion. Old things have been displaced by new; and the magnitude of the results has been extraordinary. The most important changes have been in the use of iron and steel instead of wood, and in the employment of the steam-engine in impelling ships by the paddle or the screw.