[18] “Inventions and Devises,” by William Bourne, p. 15; London, 1578. [19] Woodcroft’s “Manuscript Collection” and “Marine Propulsion,” vol. i. p. 7. [20] “Marine Propulsion” from Patent Office, Woodcroft, vol. i. p. 8. [21] Works of Roger Bacon, Hamburg, ed. 1598, pp. 74-75. [22] “Woodcroft on Steam Navigation,” pp. 3 and 4. [23] Ibid., p. 5. [24] Although there is no evidence that the Marquess of Worcester did employ steam to propel any boat, it must be allowed (in spite of the perhaps natural desire of Mr. Muirhead to exalt the genius of his relative, James Watt) that he was the first to make an actual steam-engine. Certain important points are clear from his description, viz., that the vessel in which the water was evaporated was distinct from that containing the water to be raised; that there were two vessels of similar description, the contents of which were alternately raised by the pressure of the “water rarefied by fire;” and that the water was lifted in a continuous stream by the aid of two cocks communicating with these vessels, and with the boiler. Now this is exactly the agency of steam at the present time, in that it is generated in one vessel, and used for mechanical purposes in another: indeed, it is just this distinction which shows the invention to have been a true one—for had the action of the steam been confined to the vessel in which it was produced, it would have been of no more practical use than were the experiments of Hero, De Caus, or Rivault. Complaint has been often made of the indistinctness and incompleteness of the descriptions furnished by the Marquess in his famous “Scantlings of one hundred Inventions,” but it may be doubted whether the author’s intention was really to convey knowledge of the mechanism he used, or even to indicate the physical principles on which they depend. His statement, however, is sufficient to enable any one possessing a knowledge of the mechanical qualities of steam, to understand the general nature of the machine produced. It ought also to be remembered that many of the ideas of inventions thrown out by the Marquess, as stenography, speaking statues, combination locks, &c., &c., have been since his time carried into effect. [25] “Buchanan on Steam Propelling,” Glasgow, 1816, p. 161. [26] “Bourne on the Screw-Propeller,” pp. 5 and 9. [27] Morisotus, “Orbis Maritima,” Generalis Historia divisio, fol., 1643. [28] The ferry boats at Quebec plying between the opposite sides of the river St. Lawrence were, at a very recent period, if they are not so still, propelled by horses and oxen walking along circular platforms so as to produce a power applied to the paddle-wheels of the boat. And a boat of a somewhat similar kind was, in the course of the present century, employed for some time between Yarmouth and Norwich in this country.