Comparatively little attention has been given to the natural history of Lewis. Stray notices of the geology, botany, and zoology of the Outer Hebrides are to be met with, but, with one or two exceptions, these are not of much value. Martin's “Description of the Western Islands (1703),” is chiefly interesting for its full account of the industrial and moral condition of the people. Little, however, can be made of his incidental references to the natural history of the islands. Two volumes on the “Economical History of the Hebrides,” by Rev. Dr Walker, Professor of Natural History in the University of Edinburgh, were published in 1808, after Dr Walker's death. This work contains a good deal of information on indigenous plants, but almost none on zoology. Dr Maculloch's “Description of the Western Islands of Scotland (3 vols., 1819)” is in every way an abler and better work than either of the two now named. Its notices of the geology and mineralogy of the Outer Hebrides are even still valuable.