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.

Well acquainted with the first principles of natural philosophy, he
had considerable advantages over his contemporaries; and his
superiority was soon acknowledged. He was not, however, on this
account inclined to remit his industry; he attended the lectures of
the ablest professors of the day, and more particularly those of Dr.
Black, with the most scrupulous punctuality, and endeavoured to
elucidate his subject by every