At length on reaching the age of seventeen he became stirred with military ambition, and, dissatisfied with his present prospects, he left his position with its opportunities for the future, and entered the Swedish army as ensign of a regiment of Field Chasseurs. This regiment was famous for its rifle practice, and Ericsson was soon one of its most expert marksmen. The routine of army life was, however, far from being sufficient to satisfy the uneasy genius of John Ericsson, and we soon find him engaged in topographical surveying for the Government, and so rapid and industrious in his work that as the surveyors were paid in accordance with the amount accomplished, he was carried on the pay rolls as two men, and paid as such, in order that the amount which he received might not seem too excessive for one individual. Even this was not sufficient to exhaust his energy, and about this time he conceived the idea of publishing a book of plates descriptive of the machinery commonly employed in the mining operations of his day. To this end he collected a large number of sketches which he had prepared in his earlier years, and made arrangements to take up the work of preparation for publication. The drawings selected were to be engraved for the book, and, nothing daunted by the undertaking, Ericsson proposed to do this work himself. After some discouragement the engraving was undertaken, and eighteen copper plates of the sixty-five selected, averaging in size fifteen by twenty inches, were completed within a year. In various ways the project met with delays, and it soon became apparent that the rapid advance in the applications of machinery to mining would render the work out of date, and it was at length abandoned.
At about this time Ericsson seems to have taken up seriously his work on his so-called "flame-engine," certain experiments made by his father having suggested to him the hope that a source of power might in this way be developed which would be more economical than the steam-engine. At this point we see entering into Ericsson's life an idea which never left him, which controlled much of his work in mid-life, and which attracted no small part of his attention throughout his closing years. This idea was the discovery of some form of heat-engine which should be more economical than the steam-engine, especially as it was in his day. The flame-engine idea grew rapidly, and soon absorbed his chief attention. Military life now lost its attraction, and in 1826 obtaining leave of absence he left his native land and turned his face toward London, doubtless with the hope strong within him that a substitute for the steam-engine had been found, and that his future lay secure and easy before him.
The characteristic features of Ericsson's life up to this time, when he had reached his twenty-third year, are energy, industry, independence, all in most pronounced degree, and combined with a most astonishing insight into mechanical and scientific questions. It was not a period of achievement, but one of formation and of development in those qualities which were soon to make him famous in both worlds. Of his work during this period of life little or nothing outside the idea embodied in the flame-engine can be said to belong to the permanent record of his life's achievement. This appeared in the "Caloric" engine, and still later in the well-known Ericsson "Air" engine of the present day.
This era was one of development and promise, and richly were the promises fulfilled in the achievements of his later years. A careful study of his life to this point is sufficient to show that, with health and time, such a nature would certainly leave a mark wide and deep on the world in which it was placed. His characteristics were such that achievement was the very essence of life, and, with the promise and potency as revealed in this first twenty-three years of his life, we may be well prepared for the brilliant record of the remaining sixty-three.
With Ericsson's arrival in London began the second important period of his life. His first efforts were directed toward the introduction of the flame-engine, but he soon found unexpected difficulties in the use of coal as fuel instead of wood, and it became clear that in order to live he must turn his attention to other matters for a time. Then followed a series of remarkable pieces of work in which Ericsson's genius showed itself, either in original invention or in the adaptation and improvement of the existing facts and material of engineering practice. While thus occupied, his leave from his regiment expired, and he seems to have overlooked taking proper steps to have it renewed. He was thus placed technically in the attitude of a deserter. Through the intervention of a friend, however, he was soon afterward restored, and promoted to the rank of Captain in the Swedish Army. This commission he immediately resigned, and thus his record became technically cleared of all reproach.
To give a mere list of the work with which Ericsson was occupied during the years from 1827 to 1839, when he removed to the United States, would be no small task, and reference to the more important only can be here made. Compressed air for transmitting power, forced draft for boilers by means of centrifugal blowers, steam boilers of new and improved types, the surface condenser for marine engines, the location of the engines of a ship for war purposes below the water line, the steam fire-engine, the design and construction of the "Novelty" (a locomotive for the Rainhill contest in 1829, when Stephenson's "Rocket" was awarded the prize, though Ericsson, heavily handicapped in time and by lack of a track on which to adjust and perfect the "Novelty," achieved a result apparently in many ways superior to Stephenson's with the "Rocket"), various designs for rotary engines, an apparatus for making salt from brine, further experimental work with various forms of heat, or so-called "caloric" engines, and the final development, in 1833, of a type from which great results were for a time expected, superheated steam and engines for its use, a deep-sea-sounding apparatus embodying the same principle as that later developed by Lord Kelvin in the well-known apparatus of the present day, a machine for cutting files automatically, various types of steam-engines, and finally his work in connection with the introduction of the screw-propeller as a means of propulsion for steam vessels. These are some of the important lines of work on which Ericsson was engaged during the twelve years of his life in London. In connection with some he was undoubtedly a pioneer, and deserves credit as an original inventor; in connection with others, his work was that of improvement or adaptation; but in all his influence was profound, and the legacy which we have received from this period of engineering progress is due in no small degree to Ericsson, and to his work in London during these years. At a later point we shall refer in some further detail to these questions, but desire for the moment, rather, to gain a broad and comprehensive view of his life as a whole.
Ericsson has been by some called a spendthrift in invention, and the term is not without some justice in its application. His genius was uneasy, and his mind was oppressed by the wealth of his ideas. It was this very wealth which led him from one idea to another, without always taking sufficient time in which to develop and perfect his plans. Rich in invention, he cared but little for exploitation, and when the truth of his predictions was demonstrated, or the ground of his expectation justified, he was eager for new achievements and new combinations of the materials of engineering progress. In this spirit of struggle and unrest, he passed the years in London, rapidly becoming known for his versatility in invention, and for his daring and originality in the details of his engineering work. From 1833 to 1839, or during the second half of this term of residence in London, he became in increasing measure absorbed in his work connected with the screw-propeller as a means of marine propulsion.
Ericsson's name in the popular mind has been most commonly associated with the "Monitor" and her fight with the "Merrimac" in the Civil War, and next, probably, with the screw-propeller as a means of marine propulsion. It will, therefore, be proper at the present point to refer in some further detail to the circumstances connected with his relation to the introduction of the screw-propeller.
Regarding this question an entire volume might be written without doing more than justice to the subject, but only a brief statement of the chief facts can be here attempted.
As early as the Seventeenth Century the possibility of developing a propulsive thrust by the use of a submerged helicoidal, or screw, propeller, had been vaguely recognized, and during the following, or Eighteenth Century, the same idea had been brought forward. It had been viewed in this connection, however, merely as a curiosity, and led to no immediate results. Later, in 1804, Francis B. Stevens, of New Jersey, in an experimental boat on the Hudson, operated twin screws, and demonstrated their applicability to the requirements of marine practice. These propellers, in fact, had a form far more nearly approaching the modern screw-propeller than did those which came somewhat later, and which marked the real entry of the screw-propeller into actual and practical service.