Whilst a schoolboy, the susceptibility of his mind, and a diffidence of character connected with it, caused him to associate very little with his schoolfellows: he dreaded the displeasure of his preceptor, as the greatest misfortune which could befal him The moment he arrived at home, he set about preparing his lesson for the next day; and as soon as this was accomplished, he amused himself by contriving small pieces of mechanism, which he exhibited with conscious satisfaction to his friends. His temper was warm and enthusiastic; whatever came within the narrow circle of his early knowledge he would attempt to imitate. He saw no difficulties before hand, nor was he discouraged when he met with them. At the early age of eleven years, he had somewhere seen a dial and a quadrant, and was able to imitate these instruments, nay, with the assistance of the latter, and the small knowledge of arithmetic and trigonometry, which he had then obtained, he formally marched out with his younger brother, and rudely attempted to measure the height of a mountain behind his father's house. When he was nearly fifteen years of age, he was, at his earnest desire, put apprentice to the celebrated mathematician, Mr. Dawson, of Sedbergh, who was at that time a surgeon and apothecary. This situation was peculiarly advantageous to him, on account of the great mathematical knowledge of his master, by whom he was instructed in the different branches of this science; and, notwithstanding his constant employment in necessary business, his ardent pursuit of professional information, and his extreme youth, in the course of four years, he became well acquainted with mechanics, hydrostatics, optics, and astronomy. He afterwards applied himself with energy to the study of chemistry, and other subjects, with which it was thought expedient that he should be acquainted, previously to attending the medical lectures in the University of Edinburgh. Strongly impressed with a sense of the value of time, he was indefatigable in the pursuit of knowledge: by a concurrence of fortunate circumstances, his talents had become so flexible, that he succeeded almost equally well in every subject to which he applied himself; but of chemistry he was particularly fond, and from this time it became his favourite study. During the four years of his apprenticeship, his conduct was in every respect highly commendable; he was assiduous, he was virtuous. His pursuit after general knowledge was restrained to one object only at a time; he had advanced far in the abstruse sciences; his inclination for study was increased: when in the year 1785, he went to Edinburgh with a degree of scientific knowledge, seldom attained by young men beginning the study of medicine. He became a member of the Medical and Physical Societies, where he soon made himself conspicuous, and of the latter of which, he was afterwards president.