JOHN ERICSSON 315 of the railway and to the competing locomotive builders. Toasts and speeches followed ; and if Ericsson did not carry home with him the ^500 offered as a prize, he at least made himself known to all England as one of the rising men of his profession. Ericsson's long-cherished plan of a caloric engine was realized in 1833, and was hailed with astonishment by the scientific world of London. Lectures were delivered on it by Dr. Dionysius Lardner and Michael Faraday, and it was much praised by Dr. Alexander Ure and Sir Richard Phillips. In 1836 Ericsson in- vented and patented the screw propeller, which revolutionized navigation, and in 1837 built a steam vessel having twin screw propellers, which on trial towed the American packet-ship Toronto at the rate of five miles an hour on the river Thames. In 1838 he constructed the iron screw steamer Robert F. Stockton, which crossed the Atlantic under canvas in 1839, an d was afterward employed as a tug-boat on the Delaware River for a quarter of a century. Within ten years Ericsson patented thirty inventions considered by him of sufficient importance to claim a place in the list that in 1863 numbered one hundred. A notable feature of the admirable work of Mr. Church is the elucidation of the truth, so often overlooked, that events never spring into being disjoined from antecedents leading to them. He explains how the varied achievements of John Ericsson were developed, showing with great force and in imperishable colors the steps to his successes, and the help the famous engineer derived in later life from the studies and experiments of his earlier career. Mr. Church, as the literary executor of Ericsson, has had unrivalled opportunities for examining the accumulation of data which throw light all along the way, and while dealing with the masterly engineering exploits of his subject, does not forget that he had a human side, and presents him with all his hopes and fears and failures, his aims, his obstacles, his courage, and his habits and eccentricities. Ericsson certainly cherished a very high ideal, and was free to an unusual extent from mercenary motives. His inventions did not always pay ; he found this a weary world for those who see beyond their fellows. Some of his mechanical contrivances in common use to-day dated so far back of the memory of any one living that before he died he often learned that he was supposed to have copied from others what he, in fact, originated himself or first brought into use. The barriers of tradition and prejudice had to be overcome with his every new invention. The introduction of steam in any shape to the English navy was sharply opposed. It is interesting to trace the incidents, apparently without con- nection, which stand in orderly relations one to another as essential parts of an intelligent design. Ericsson was in America at the critical moment when all the experiences of his previous life were to be brought into full play ; when he was to take part in an enterprise involving the existence of a nation, the hopes of hu- manity. He was ready to meet the strain of a demand to which no other living man was adequate. He was then fifty-eight years of age, with the constitution and the vital forces of a man of forty, and such experience in actual accomplish, ment as few acquire in the longest span of a lifetime.