The next day Count Platen found John anxiously awaiting him. He told the boy at once that his plan had proved successful, and that both John and Nils were to be enrolled as cadets in the mechanical corps of the Swedish navy, and that John was to be put in charge of part of the canal building. The boy was highly delighted; he knew that now he should have a chance to try in actual working some of the inventions he had planned on paper. As soon as he had thanked his kind friend the Count he ran home to tell his mother the news of Nils' and his good fortune.
It was a curious sight when the officer in command of the troops placed six hundred soldiers in charge of young John Ericsson. They were too well trained to laugh, but they were tremendously surprised when they saw that their future orders were to come from this small, curly-haired lad just barely turned fourteen. Olof Ericsson himself was scarcely less surprised than the men; he knew his son's great mechanical ability, but he could hardly believe that others had come to realize it so soon.
A few days of actual work on the canal, however proved that Count Platen had made no mistake. John knew what ought to be done, and he could show the soldiers new and better ways of getting results, although he was actually too small to reach the eyepiece of his leveling instrument without the aid of a camp-stool which he carried about with him. He brought out some of the mechanical drawings he had worked over, and had machinery made after them, and whenever his inventions were tried they met with success.
For several years John commanded his six hundred men at the Göta Canal, and then he decided to enter the army. He had grown tall, and was noted for his great strength and skill in feats of arms. At seventeen he was made an Ensign in the Rifle Corps, and soon after Lieutenant in the Royal Chasseurs. He was fond of the life of the army, but he saw there was no great future in it for him, and he could not give up his passion for science and invention. He procured an appointment as surveyor for the district of Jemtland, and found himself free again to work on his own lines.
Sweden is a rugged country, its northern part serried by great fiords, its mountains steep and often desolate, its forests thick and many. The young surveyor was in his element roughing it through the wild country, with an eye to improving it for cultivation and for defense, making elaborate maps of its hills and valleys, and charts of its fiords and bays. He had a genius for such work, and the drawings he sent back to Stockholm were invaluable for the development of Sweden. The surveyors were paid according to the work they did, but John Ericsson worked so rapidly that the officials were afraid it would cause a scandal if it were known how much money he was receiving, and so they carried him on their account-books as two different men and paid him for two men's work.
In his spare hours in Jemtland and Norrland John was busy with inventions. As a boy he had been delighted to watch his father make a vacuum in a tube by means of fire. Now he worked over uses to which he could put that idea, and finally invented a flame engine based largely on that principle. That success led him to study engines more deeply, and had much to do with deciding his later career.
Sweden had shown the world much that was new in the building of the Göta Canal, and many of the improvements had been due to the boy cadet Ericsson. He was now persuaded to write a book on "Canals," explaining his inventions and describing the Swedish plans. In such a scientific book the drawings of diagrams were as important as the writing. As soon as John realized that, he could not resist the temptation to try his hand at inventing a machine which should properly engrave the plates he was drawing. It was pure delight to him to exercise his wits on such a problem, and as a result in a short time he had made a machine for engraving plates which was used successfully in preparing the illustrations for his book on "Canals."
The youth had now won wide recognition throughout Sweden for his inventive skill. But his own country offered him small opportunities, devoted though he was to the land and the people. There was more chance for such a man in a country like England, and there he now went. Stephenson was working then on his steam-engine, and Ericsson studied the same subject, and built an engine which in many ways was superior to the Englishman's. In whatever direction he turned his mind he was able to find new ideas for improving on old methods.
Ericsson soon built a locomotive for the directors of the railway between Liverpool and Birmingham which was the lightest and fastest yet constructed, starting off at the rate of fifty miles an hour. He could not find the opportunities he wished, however, in England, and went to Germany, and from there came to the United States.
It was in America that Ericsson won his greatest triumphs. He had invented a screw propeller for boats, and found a splendid market for this type of machinery. He built the steamship Princeton, the first screw steamer with her machinery under the water line. This was a great improvement on the old top-heavy style of steamboats, but how great was only to be known when war showed that ironclads with machinery safely sunk beneath the water line and so out of reach of the enemy's guns were to revolutionize naval warfare.