their report on Deep Sea Deposits, still the standard work of reference, notable alike for its detail and its clear generalizations. As a consequence of this work, samples of deposits obtained by surveying ships and by various expeditions were sent to Murray, and a unique collection was thus brought together. Another result of Murray's observations during the expedition was his well-known paper On the Structure and Origin of Coral Reefs and Islands (Proceedings of the Royal Society of Edinburgh, vol. x, 1880), in which he dissented from Darwin's view that the form of atolls was due to subsidence of the land forming the foundation of the reef. Murray put forward the view that submarine elevations were built upwards by deposition on their summits of the skeletons of pelagic organisms and other sediments, and that when they reached a height favourable for the growth of any coral polyps which became established upon them, coral plantations were formed. He held that as these approached the surface of the sea they would assume the atoll form owing to the more abundant supply of food and more vigorous growth on the outer margin, and to the removal of dead coral from the interior portion by currents and by solution. Murray's work was stimulating, and, although his explanation of the formation of atoll lagoons is not generally accepted by recent authorities, his conclusions on other points, e.g. the importance of submarine planation, have proved to be sound. Murray was joint author of the Narrative of the Cruise of H.M.S. Challenger (1885), and he drew up the last two volumes of the Report (1895), which form an impressive summary of the results of the expedition.
In 1880 and 1882 Murray engaged, with Captain T. H. Tizard, in exploring the Faroe Channel in the government surveying ships Knight Errant and Triton. He established small marine laboratories at Granton and at Millport, and the latter has developed into the Scottish Marine Biological Association. Murray's steam yacht, the Medusa, built and equipped for marine biological work, enabled him with the help of several younger colleagues to bring together during the years 1884–1892 a large number of records, published in 1918 by his former secretary, J. Chumley, under the title The Fauna of the Clyde Sea Area.
As soon as the Challenger work was out of his hands, Murray undertook a bathymetrical survey of the fresh-water lochs of Scotland. Supported by the councils of the Royal Societies of London and of Edinburgh, he had urged the government to undertake this survey, but without avail. In 1897 with his capable young collaborator, Frederick Pullar, he began the work, and several important papers on the results had appeared, when in 1901 Pullar was drowned while attempting to save the lives of others. His father—Laurence Pullar, Murray's oldest friend—determined that the survey should be continued, and provided funds for a staff of assistants; they began work in 1902 and carried on the investigations until 1909. Some 60,000 soundings were made in 562 lochs, and the records of these and of other scientific results, forming an admirable survey, were published in six volumes by Murray and Pullar in 1910.
When the Challenger office was closed (May 1895), Murray bought a house near his residence to serve as a library and laboratory. Here were arranged the series of oceanic deposits, until in 1921, with the greater part of his library, they were removed to the British Museum (Natural History); here also were the head-quarters of the Lake Survey. To this centre came many investigators whom Murray inspired and assisted out of the fullness of his experience.
As the result of his detection of phosphate of lime in rock specimens brought in 1887 from Christmas Island, in the Indian Ocean, Murray urged the annexation of the island, which took place the next year. In 1891 Murray and G. Clunies Ross, of the Cocos Islands, obtained a lease of Christmas Island, and in 1897 they formed a small company to develop its valuable resources. Murray also paid the expenses of two scientific expeditions to the island in 1897–1898 and in 1908, as the result of which Dr. C. W. Andrews, of the British Museum (Natural History), brought home extensive collections. A Monograph of Christmas Island (1900), which embodies the results of the first expedition, is important as forming a record of the indigenous fauna and flora of an isolated tropical island before these had become affected by the animals and plants introduced by man. Murray himself made two exploring visits (1900, 1908) to the island. He used to say that the Treasury had received from the island in the form of rents, royalties, and taxes a sum which exceeded the cost of the Challenger expedition and the publication of its results.
In 1909 Murray visited Copenhagen and urged upon the international council for the exploration of the sea the need for systematic observations in the north At--
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