Mr. Rankine's literary career commenced while he was in Edinburgh with the publication of a series of papers on the mechanical action of heat. His theory of the development of heat as one of the forces of thermo-dynamics was propounded simultaneously with that of Professor Clausius of Berlin, in 1849, and supplied the only link that was wanted to make the theory of the steam engine a perfect science. For his researches on this subject he received the Keith Medal of the Royal Society of Edinburgh in 1852. Of miscellaneous literature connected with the science of mechanics he has been a most voluminous writer. He has contributed a number of valuable papers to the Institution of Naval Architects, of which for many years he has been a prominent member. In 1864 he read before that Society papers on "The Computation of the Probable Engine Power and Speed of Proposed Ships," "On Isochronous Rolling Ships," and on "The Uneasy Rolling of Ships." In the following year he read a paper on "A Proposed Method of Bevelling Iron Frames in Ships;" and, in 1866, he read two papers--one of them demonstrating the means of finding the most economical rates of expansion in steam engines, and the other describing a balanced rudder for screw steamers. But he did not confine his contributions to one Institution, or even to one medium of publication, for we find that he read a number of papers before the Philosophical Society, the Royal Society of Edinburgh, and the Institution of Engineers and Shipbuilders in Scotland, while he wrote occasionally at the same time for the _Philosophical Magazine_, the _Journal of the Royal United Service Institution_, and other leading publications. His first appearance in the pages of the _Philosophical Magazine_ was made in 1842, when he wrote a paper on an experimental inquiry into the advantages attending the use of cylindrical wheels on, with an explanation of the theory of adopting curves for these wheels, and its application to practice, and an account of experiments showing the easy draught and safety of carriages with cylindrical wheels. From this time, until he made his _debut_ at the Royal Society of Edinburgh in 1853, he had been working most assiduously at his theory of the development of heat, and one of his first papers to the Royal Society was entitled "A Review of the Fundamental Principles of the Mechanical Theory of Heat, with Remarks on the Thermic Phenomena of Currents of Elastic Fluids, as Illustrating those Principles." In 1858 he published "A Manual of Applied Mechanics and other Prime Movers," in 1859 he produced another masterly work on "Civil Engineering," and in 1866 "Useful Rules and Tables Relating to Mensuration" came from his prolific pen. In 1865 he published, in conjunction with his friends Mr. James R. Napier, Mr. Isaac Watts, C.B., and Mr. F. K. Barnes, of the Constructors' Department of the Royal Navy, a treatise on "Shipbuilding,