_Fourth Crusade._—Led by Baldwin, Count of Flanders, with aid from Venice, A.D. 1202. Results: taking of Zara and of Constantinople, A.D. 1204. The remaining Crusades were, comparatively, unimportant. [368] Gibbon, ch. lxiii. [369] So late as Chardin, four hundred sail of vessels were occupied at Caffa during forty days in the corn and fish trade. (“Voy. en Pérse,” i. pp. 46-48.) Clarke found it wholly demolished by the Russians (“Travels,” i. p. 144)—and so it is now. [370] Gibbon, ch. lxiii. [371] The precise era of the invention and application of gunpowder is involved in doubt, and has formed the subject of many learned disquisitions, not the least interesting of which will be found in the 1st and 2nd vols. of Bishop Watson’s “Chemical Essays.” CHAPTER IX. Ancient galleys—Different descriptions—Their outfit—Beaks—Stern—Masts and sails—Oars—Mode of rowing—Single-banked galleys—French galley—General Melvill’s theory—Charnock’s theory—Vossius’s views—Mr. Howell’s plan—Plan of Revd. J. O. W. Haweis (Appendix No. 1)—Our own views—Biremes—Triremes—Quadriremes—Quinqueremes—Hexiremes and larger galleys—Suggested plan of placing the rowers—Summary. [Sidenote: Ancient galleys.] Frequent reference has been made in the course of this work to the row-galleys of the ancients, and no subject connected with shipping has called forth more conflicting opinions: nor is this surprising. Most ancient writers who refer to it are less or more at variance with each other; while the representations on coins and monumental sculptures are generally on so small a scale as to afford little assistance in its elucidation. Within the last two centuries numerous authors have endeavoured to solve the problem how these galleys were classed and rowed, and to establish a system of propulsion which, while applicable to every class, would harmonize with the accounts preserved of the size of these vessels and of the number of rowers employed on board of them. [Sidenote: Different descriptions.] Galleys appear to have been rated by their bank of oars, that is, uniremes had one, biremes two, triremes three, quadriremes four, quinqueremes five, and so forth, up to the enormous ship of Ptolemy Philopator, which we have already noticed. But the chief point of controversy has been what constituted a bank.