he encountered the work of Descartes which first attracted him to
metaphysics. There, too, he met Pocock, the Arabic scholar, and Wallis
the mathematician, who must at least have commanded his respect. In 1659
he accepted a Senior Studentship of his college, which he retained until
he was deemed politically undesirable in 1684. After toying with his
father's desire that he should enter the Church, he began the study of
medicine. Scientific interest won for him the friendship of Boyle; and
while he was administering physic to the patients of Dr. Thomas, he was
making the observations recorded in Boyle's _History of the Air_ which
Locke himself edited after the death of his friend.

Meanwhile accident had turned his life into far different paths. An
appointment as secretary to a special ambassador opened up to him a
diplomatic career; but his sturdy commonsense showed him his unfitness
for such labors. After his visit to Prussia he returned to Oxford, and
there, in 1667, in the course of his medical work, he met Anthony
Ashley, the later Lord Shaftesbury and the Ahitophel of Dryden's great
satire. The two men were warmly attracted to each other, and Locke
accepted an appointment as physician to Lord Ashley's household. But he
was also much more than this. The tutor of Ashley's philosophic
grandson, he became also his patron's confidential counsellor. In 1663
he became part author of a constitutional scheme for Carolina which is
noteworthy for its emphasis, thus early, upon the importance of
religious toleration. In 1672, when Ashley became Lord Chancellor, he
became Secretary of Presentations and, until 1675, Secretary to the
Council of Trade and Foreign Plantations. Meanwhile he carried on his
medical work and must have obtained some reputation in it; for he is
honorably mentioned by Sydenham, in his _Method of Curing Fevers_
(1676), and had been elected to the Royal Society in 1668. But his real
genius lay in other directions.