But when the _Great Britain_ was being built the greater efficiency of the screw-propeller for ocean voyages was not widely understood. She was a fine vessel, over 320 feet long, 51 feet wide, and 32½ feet deep. Her screw was successful; but on her fourth voyage to New York she became stranded in Dundrum Bay, and lay aground for nearly a year. Incidentally, however, this catastrophe seems to have given great impetus to iron shipbuilding; for after being floated, she was discovered to have suffered but comparatively slight damage. She was seen in dock by many persons interested in shipping, and they became impressed with the practicability and usefulness of iron for shipbuilding. Unfortunate _Great Britain_! She passed through many vicissitudes. Her owners got into difficulties, and after some alterations, she ran to Australia, and at length she wheezed her way to the Falkland Islands, where, it is said, she served as a hulk—a sorry end to a successful beginning. The engines of the early screw vessels appear to have very much resembled those for paddle-wheels ships. Thus the _Rattler_, engined by Messrs. Maudslay for the Admiralty about the year 1841, had upright cylinders, with a crank-shaft overhead and wheels to give speed to the screw. In the meantime, however, the commercial difficulty of transatlantic steam traffic was being solved. The something lacking had been supplied. What was it? CHAPTER IV. THE OCEAN RACE. “This is the very opportunity I have been wanting!” The speaker was looking at a paper setting forth that the British Government were open to consider contracts for the carrying of the letters by steamships between Great Britain and America. Encouraged, no doubt, by the success attending the conveyance of the mails by similar means to the Peninsula, the Government were now going farther afield. The practicability of ocean steam traffic had been amply demonstrated; but some of those early steamships did not “pay,” and to that test, after all, such undertakings must come. Now, the man into whose hands the circular had fallen was of great intelligence and remarkable energy. He was a merchant and owner of ships, and agent for the East India Company at Halifax, Nova Scotia. His name has since become known the wide world over. It was Samuel Cunard. Apparently he had cherished the idea of establishing transatlantic steam traffic for some years—since 1830 it is said—and now, here was the opportunity. The British Government would, of course, give a handsome sum for carrying the mails, and that sum would form a backbone to the enterprise.