in widely separated islands was explained by physical means of transport, and the present trend of opinion is on his side. Hooker told him that following Edward Forbes [q. v.] he was driven to 'the necessity of assuming the destruction of considerable areas of land to account for it' (L. L. ii. 20). This was the view adopted in the 'New Zealand Flora' in 1854.
In 1845 Hooker was a candidate, with the support of Humboldt and Robert Brown [q. v.], for the chair of botany at Edinburgh, but was unsuccessful. Immediately afterwards he was appointed botanist to the Geological Survey. His work in a new field was brilliant ; in papers published in 1845 he threw light on the structure of Stigmaria and Lepidostrobus, and in 1852 explained Trigonocarpon. He did no further work in fossil botany after 1855.
Hooker wrote to Darwin in 1854, 'from my earliest childhood I nourished and cherished the desire to make a creditable journey in a new country' (M. L. i. 70). This was gratified in 1847 (in which year he was elected F.R.S.), when Lord Carlisle, then chief commissioner of woods and forests, obtained for him a grant of 400Z. wherewith to explore for two years the central and eastern Himalaya. The earl of Auckland wished this to be followed by a visit to Labuan, for which he received a commission in the navy. But this part of the scheme fell through with Lord Auckland's death in 1849. The admiralty sent him out to Egypt in H.M.S. Sidon with Lord Dalhousie, who attached him to his suite. Part of 1848 and 1849 was spent in exploring Sikkim, where he was the guest of Brian Hodgson [q. v.]. In the latter year he was joined by Dr. Campbell, the government agent, and owing to some intrigue in the Sikkim court they were both temporarily imprisoned. He was able to explore part of Eastern Nepal, in which no traveller has since succeeded in following him. He surveyed single-handed the passes into Tibet, and the Lhasa expedition in 1903 sent him a telegram from Khambajong congratulating him on the usefulness of his survey. His observations on the geology and meteorology of Sikkim are still fundamental, and he explained the terracing of mountain valleys by the formation of glacial lakes. He succeeded in introducing into cultivation through Kew the splendid rhododendrons of Sikkim, which were worthily illustrated from his drawings in a work edited by his father (1849-51) and published during his absence. Hooker spent 1850 in travelling with Thomas Thomson (1817-1878) [q. v.] in Eastern Bengal and the Khasia Hills. They returned to England together in 1851. The result of the expedition was a collection of plants representing 6000 to 7000 species. The treasury gave him a grant of 400l. per annum for three years to name these and distribute the duplicates (sixty herbaria were recipients), and to write the 'Himalayan Journals' (1854; 2nd edit. 1855), which have become a classic. In 1855 he published 'Illustrations of Sikkim-Himalayan Plants,' including Hodgsonia, the gigantic cucurbit dedicated to his friend Hodgson.
In 1855 Hooker was appointed assistant director at Kew, and with Thomson published his first volume of a 'Flora Indica,' which, planned on too large a scale, did not proceed further. It was prefaced by an introductory essay on the geographical relations of the flora which has never been superseded. The authors regard species as 'definite creations' (p. 20). But both Darwin and Hooker were always in agreement that species for purposes of classification must be accepted as facts, whatever view be taken as to their origin. Huxley, however, thought Hooker in the following year 'capable de tout in the way of advocating evolution' (L. L. ii. 196).
In 1858 an event happened which Darwin's friends had long anticipated. On 15 June Darwin received from Dr. Alfred Russel Wallace, who was then in the Celebes Islands, an essay which substantially embodied his own theory. The position became tragic, for on 29 June Darwin was prostrate with illness ; scarlet fever was raging in his family and an infant son had died of it the day before. Lyell and Hooker acted for him ; an extract from an abstract of the theory shown by Darwin to Hooker and read by the latter in 1844 was communicated with Wallace's essay to a meeting of the Linnean Society on 1 July 1858. Darwin's 'Origin' itself appeared in Nov. 1859. Four months earlier Hooker published his 'Introductory Essay on the Flora of Tasmania,' by far the most noteworthy of his speculative writings. In this he frankly adopts, in view of the Darwin-Wallace theory, the hypothesis 'that species are derivative and mutable.' The essay is in other respects remarkable for the first sketch of a rational theory of the geographical distribution of plants, besides giving a masterly analysis of the Australian flora.
In the autumn of 1860 John Washington [q. v.], hydrographer of the navy, invited Hooker to take part in a scientific expedition to Syria. The cedar grove on Lebanon
