"My first essay at making a steam engine was when I was fifteen. I then made a real working; steam-engine, 1 3/4 diameter cylinder, and 8 in. stroke, which not only could act, but really did some useful work; for I made it grind the oil colours which my father required for his painting. Steam engine models, now so common, were exceedingly scarce in those days, and very difficult to be had; and as the demand for them arose, I found it both delightful and profitable to make them; as well as sectional models of steam engines, which I introduced for the purpose of exhibiting the movements of all the parts, both exterior and interior. With the results of the sale of such models I was enabled to pay the price of tickets of admission to the lectures on natural philosophy and chemistry delivered in the University of Edinburgh. About the same time (1826) I was so happy as to be employed by Professor Leslie in making models and portions of apparatus required by him for his lectures and philosophical investigations, and I had also the inestimable good fortune to secure his friendship. His admirably clear manner of communicating a knowledge of the fundamental principles of mechanical science rendered my intercourse with him of the utmost importance to myself. A hearty, cheerful, earnest desire to toil in his service, caused him to take pleasure in instructing me by occasional explanations of what might otherwise have remained obscure. "About the years 1827 and 1828, the subject of steam-carriages for common roads occupied much of the attention of the public. Many tried to solve the problem. I made a working model of an engine which performed so well that some friends determined to give me the means of making one on a larger scale. This I did; and I shall never forget the pleasure and the downright hard work I had in producing, in the autumn of 1828, at an outlay of 60L., a complete steam-carriage, that ran many a mile with eight persons on it. After keeping it in action two months, to the satisfaction of all who were interested in it, my friends allowed me to dispose of it, and I sold it a great bargain, after which the engine was used in driving a small factory. I may mention that in that engine I employed the waste steam to cause an increased draught by its discharge up the chimney. This important use of the waste steam had been introduced by George Stephenson some years before, though entirely unknown to me.