By the time I was seventeen years old I had acquired a considerable amount of practical knowledge as to the use and handling of mechanical tools, and I desired to turn it to some account. I was able to construct working models of steam-engines and other apparatus required for the illustration of mechanical subjects. I began with making a small working steam-engine, for the purpose of grinding the oil-colors used by my father in his artistic work. The result was quite satisfactory. Many persons came to see my active little steam-engine at work; and they were so pleased with it that I received several orders for small workshop engines, and also for some models of steam-engines to illustrate the subjects taught at Mechanics' Institutions. I contrived a sectional model of a complete condensing steam-engine of the beam and parallel-motion construction. The model, as seen from one side, exhibited every external detail in full and due action when the fly-wheel was moved round by hand; while on the other, or sectional side, every detail of the interior was seen, with the steam-valves and air-pump, as well as the motion of the piston in the cylinder, with the construction of the piston and the stuffing-box, together with the slide-valve and steam-passages, all in due position and relative movement. I was a regular attendant at the Edinburgh School of Arts from 1821 to 1826, meanwhile inventing original contrivances of various sorts. About the year 1827, when I was nineteen years old, the subject of steam-carriages to run upon common roads occupied considerable attention. Several engineers and mechanical schemers had tried their hands, but as yet no substantial results had come of their attempts to solve the problem. Like others, I tried my hand. Having made a small working model of a steam-carriage, I exhibited it before the members of the Scottish Society of Arts. The performance of this active little machine was so gratifying to the Society, that they requested me to construct one of such power as to enable four or six persons to be conveyed along the ordinary roads. The members of the Society, in their individual capacity, subscribed £60, which they placed in my hands, as the means of carrying out their project.