his athletic excellence gratified him even more than official recognition of his intellectual achievements. His literary power was shown by his winning the college declamation prize in 1866, in consequence of which he was appointed to deliver the usual oration at the college commemoration in the following December, when he pronounced a characteristic panegyric upon Whewell, then recently dead. He was a member of the well-known club generally called the 'Apostles,' and had many friends among his most distinguished contemporaries, especially Professor Pollock, afterwards his biographer. He was at this time a high churchman. He had studied Aquinas, and was fond of supporting catholic doctrines with ingenious scientific analogies. This phase was dispelled by his study of Darwin and Mr. Herbert Spencer, under whose influence he worked out the dominant ideas of his later writings.
In 1868 Clifford was elected to a fellowship at Trinity, and was a resident until 1871. In 1870 he joined the English Eclipse expedition, and was wrecked in the Psyche off Catania. The ship was entirely lost, but the instruments and all hands were saved. During his Cambridge residence he became intimate with Professor Fawcett, and was secretary to the Republican Club, of which Fawcett was a member. In 1871 he was appointed professor of applied mathematics at University College, London. In 1874 he was elected fellow of the Royal Society, a distinction for which he had modestly refused to be nominated at an earlier period. His reputation was rapidly spreadingbeyond purely scientific circles. He was a singularly effective lecturer. On 6 March 1868 he had delivered a discourse at the Royal Institution (upon 'Conditions of Mental Development'), showing the strong impression made upon him by Mr. Herbert Spencer, and another on 18 Feb. 1870 upon 'Theories of Physical Forces.' The last showed a remarkable power of giving a popular exposition of abstruse doctrines, which won general recog- nition when, on 19 Aug. 1872, he delivered an address before the British Association at Brighton upon 'The Aims and Instruments of Scientific Thought.' Clifford spoke with extreme facility, generally from a few brief notes. He would revise his lectures from a shorthand report, or write them out from memory. He found previous writing down to be only an encumbrance. The vivacity and quaint humour of his addresses, and the relarkable felicity of illustration, interested popular hearers, and persuaded them (not always correctly) that they could follow his reasoning. In the years 1872-5 he delivered several addresses to the Sunday Lecture Society, in which he took a deep interest. He sympathised with its aim of popularising the results of scientific inquiry, and was exceptionally qualified to aid in its promotion.
On 7 April 1875 Clifford married Lucy, daughter of Mr. John Lane, a well-known Barbadian. His marriage was a source of unmixed happiness. His house became the meeting-place of a varied circle of friends of all opinions and tastes, though especially of scientific friends. Clifford was a most attractive companion. His careless phrases had always the stamp of genius. His transparent simplicity and modesty, his unflagging vivacity and his keen interest in all speculative questions were combined with admirable delicacy of perception and a most affectionate nature. Childlike to the last, he had a special talent for attracting children, and a children's party was one of his greatest pleasures. He was equally at ease with the most eminent thinkers of his day, and was from 1874 a prominent member of the Metaphysical Society, in which distinguished men of the most opposite views met for a frank discussion of fundamental questions. Some of his papers read before this society were published in 'Mind ' and the 'Contemporary Review,' and may be found in his ' Essays and Lectures.' Clifford's freedom of speech and strong sense of the ridiculous occasionally gave some pretext for a charge of levity. But the utter absence of any wish to give pain prevented offence at the time, nor could there be any doubt of the fundamental seriousness of his purpose.
From 1875 to 1878 Clifford published several reviews, not previously delivered as lectures, for which his health was now becoming a disqualification. They give his latest philosophical views. One of them (a review of the 'Unseen Universe' in the 'Fortnightly Review ' for June 1875) was written between a quarter to ten at night and nine the next morning. Another upon Virchow's address ('Nineteenth Century' for April 1878) was written in the same way. Both at Cambridge and afterwards he would not unfrequently work through the night. The disproportion between his great nervous energy and his constitutional weakness tempted him to dangerous efforts, both physical and intellectual. It was difficult to persuade him to adopt prudential measures, and he persevered even in his gymnastic exercises till after serious warnings.
In the spring of 1876 grave symptoms of pulmonary disease showed themselves. He was induced, very reluctantly, to take six months' leave of absence, which he spent with his wife in Algiers and Spain. The
