by further explorations in the Porcupine (1869 and 1870), and in the Shearwater (1871), in which he traversed the Mediterranean and the Atlantic between Great Britain and Portugal, and by the Challenger expedition under Wyville Thomson, in the preparations for which Carpenter took an active part.
Some of Carpenter's most important zoological contributions related to the question of the animal nature of Eozoön canadense, as found in masses in the Laurentian rocks of Canada. He contributed numerous papers on this subject to the Royal Society, the ‘Canadian Naturalist’ (ii. 1865), the ‘Intellectual Observer’ (vii. 1865), ‘Philosophical Magazine’ (1865), ‘Geological Society's Quarterly Journal,’ &c. For some years before his death he had been collecting materials for a monograph on Eozoön, which he did not complete. Another favourite subject of his research was the structure, embryology, and past history of the featherstars and crinoids, in which he demonstrated important facts of structure and physiology which were long controverted. His chief paper was ‘On the Structure, Physiology, and Development of Antedon rosaceus’ (‘Philosophical Transactions,’ 1866, pp. 671–756). Among his services to zoology, and in a lesser degree to botany, may be reckoned his work on ‘The Microscope and its Revelations,’ 1856, which reached a sixth edition in 1881. His zoological and botanical and other contributions to the ‘Cyclopædia of Science’ were afterwards published in separate volumes in Bohn's ‘Scientific Library.’ The ‘Comparative Physiology’ of his early ‘Physiology’ was published separately as an enlarged fourth edition in 1854.
In addition to his principal book, Carpenter's contributions to physiology were chiefly to the mental and the physical aspects of the science. His early papers were followed by others: ‘On the Mutual Relations of the Vital and Physical Forces’ (‘Philosophical Transactions,’ 1850), and ‘On the Application of the Principle of Conservation of Force to Physiology’ (‘Quarterly Journal of Science,’ i. 1864). His great work on physiology attained a fifth edition in 1855, and has subsequently been edited by Mr. Henry Power. A smaller ‘Manual of Physiology,’ 1846, reached a fourth edition in 1865. In 1874 Carpenter expanded the chapters of his previous work on mental physiology into a treatise, ‘The Principles of Mental Physiology’ (fourth edition, 1876). His views on the relation of mind and brain were acute and in advance of his time. While unsparing in his exposures of quackery in phrenology, mesmerism, electro-biology, and spiritualism, he did much to educate the public in sound views of mental processes, and especially to bring into prominence the importance of those operations of which we are unconscious. In 1851, in the ‘Proceedings of the Royal Institution,’ i. 147–53, he wrote ‘On the Influence of Suggestion in Modifying and Directing Muscular Movement, independently of Volition,’ and in 1868 (ib. v. 338–45) ‘On the Unconscious Activity of the Brain.’ He made the subject of unconscious cerebration (his own phrase) a speciality, further discussing it in a lecture at Glasgow in 1875, ‘Is Man an Automaton?’ It is worth noting that while editor of the ‘Medico-Chirurgical Review’ he published a criticism of Noble's ‘Physiology of the Brain,’ which had the effect of converting Dr. Noble. He was one of the editors of the ‘Natural History Review’ (1861–5).
Carpenter's deep-sea explorations led him into an extensive field of marine physics. He developed in this country the doctrine of a general oceanic circulation, due largely to heat, cold, and evaporation, which had been previously little suspected. His more important papers on this question are contained in the ‘Royal Society's Proceedings,’ xvii. xx.; ‘Geographical Society's Proceedings,’ xv. 1871; ‘British Association Reports,’ xli. xlii. xliii. His views were persistently assailed by Mr. James Croll and others, but have been sustained by many other writers.
Carpenter's incessant industry enabled him to take part in many public movements with effect. In 1849 he gained a prize for an essay ‘On the Use and Abuse of Alcoholic Liquors’ (1850), and he wrote further ‘On the Physiology of Temperance and Total Abstinence’ (1853). He was a singularly lucid lecturer on scientific subjects, and organised the Gilchrist scheme of popular science lectures, which has been of great value in spreading sound scientific knowledge and awakening interest in science among the working classes. He was a zealous champion of vaccination and other scientific measures for checking disease, and wrote many magazine articles on such topics. He was a large contributor to various cyclopædias. His labours received numerous marks of high distinction, including a royal medal of the Royal Society (1861), the Lyell medal of the Geological Society (1883), the LL.D. of Edinburgh (1871), the presidency of the British Association (1872), and the corresponding membership of the Institute of France (1873).
In person Carpenter was above middle height, of quiet and somewhat formal man-