Darwin's poetical prophecy was published long years before Watt's engine rendered its partial fulfillment a possibility; and thus, for many years before even the first promising effort had been made, the minds of the more intelligent had been prepared to appreciate the invention when it should finally be brought forward. The earliest attempt to propel a vessel by steam is claimed by Spanish authorities, as has been stated, to have been made by Blasco de Garay, in the harbor of Barcelona, Spain, in 1543. The record, claimed as having been extracted from the Spanish archives at Simancas, states the vessel to have been of 200 tons burden, and to have been moved by paddle-wheels; and it is added that the spectators saw, although not allowed closely to inspect the apparatus, that one part of it was a "vessel of boiling water"; and it is also stated that objection was made to the use of this part of the machine, because of the danger of explosion. The account seems somewhat apocryphal, and it certainly led to no useful results. In an anonymous English pamphlet, published in 1651, which is supposed by Stuart to have been written by the Marquis of Worcester, an indefinite reference to what may probably have been the steam-engine is made, and it is there stated to be capable of successful application to propelling boats. In 1690, Papin proposed to use his piston-engine to drive paddle-wheels to propel vessels; and in 1707 he applied the steam-engine, which he had proposed as a pumping-engine, to driving a model boat on the Fulda at Cassel. In this trial he used the arrangement of which a sketch has been shown, his pumping-engine forcing up water to turn a water-wheel, which, in turn, was made to drive the paddles. An account of his experiments is to be found in manuscript in the correspondence between Leibnitz and Papin, preserved in the Royal Library at Hanover. Professor Joy found there the following letter:[60] "Dionysius Papin, Councillor and Physician to his Royal Highness the Elector of Cassel, also Professor of Mathematics at Marburg, is about to dispatch a vessel of singular construction down the river Weser to Bremen. As he learns that all ships coming from Cassel, or any point on the Fulda, are not permitted to enter the Weser, but are required to unload at Münden, and as he anticipates some difficulty, although those vessels have a different object, his own not being intended for freight, he begs most humbly that a gracious order be granted that his ship may be allowed to pass unmolested through the Electoral domain; which petition I most humbly support. G. W. LEIBNITZ. "HANOVER, _July 13, 1707_." This letter was returned to Leibnitz, with the following indorsement: