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.