It was in America, we have seen, that progress in steam navigation was of the greatest interest to the public, and it was by Americans that the disabilities of the paddlewheel were most keenly appreciated. Two witnesses of the trial of Ericsson’s boat saw and admitted the advantages of the new method: Mr. Ogden, an engineer who had been U.S. consul at Liverpool for some years, and Captain Stockton, U.S.N. The latter appreciated the military advantages of screw propulsion and was soon its enthusiastic advocate. Under his influence and encouragement Ericsson threw up his engagements in London and went to America. “We’ll make your name ring on the Delaware,” said Captain Stockton to him at a dinner in his honour given at Greenwich. The prediction was fulfilled. In the course of time Ericsson saw his propeller applied on a large scale, not only to mercantile craft but in the American navy. Early in ’37 Captain Stockton had ordered an iron vessel to be built by Messrs. Laird, of Birkenhead, and fitted with a screw. In the following year she was launched, and in the spring of ’40, after giving demonstration on the Thames of the great towing power of her propeller, she left for America for service as a tug on the big rivers. On this work one of the great advantages of the screw was realized: the immunity with which the screw vessel could work in drift ice, when paddlewheel steamers were perforce laid up. In the meantime, fortunately, Pettit Smith’s successes had not been without their effect on opinion in this country. A company was formed to exploit the screw, and a vessel, the _Archimedes_, was built amid a strange chorus of detraction, opposition and ridicule. She made her trials in October, ’39. Her propeller was at first in the form of a complete convolution of a helical screw of 8-foot pitch and of 5 foot 9 inches diameter; but subsequently this blade was replaced by two, each of which formed half a convolution, with the two halves set at right angles to one another. Comparative trials were ordered by the Admiralty in the following year to test the merits of the _Archimedes’_ screw as compared with the ordinary paddlewheels applied to her Majesty’s mail packets on the Dover station. The results were inconclusive.[155] But a subsequent voyage round the coasts of Great Britain, during which the machinery of the _Archimedes_ was laid open to the inspection of the general public, and a later voyage from Plymouth to Oporto which recreated a new record for a steam passage, went far to establish in public estimation the merits of the new propeller. But generally the invention was discouraged. Prejudice and vested interests, rather than a reasoned conservation, seem to have operated to oppose its progress. “A striking instance of prevailing disinclination to the screw propeller was shown on the issue of a new edition of the _Encyclopædia Britannica_, in which the article on steam navigation contained no notice whatever of the subject.”