BEING AN ADDRESS DELIVERED TO THE BIOLOGICAL SECTION OF THE BRITISH ASSOCIATION (GLASGOW; SEPTEMBER 6TH, 1876) AS PRESIDENT OF THE Introductory Remarks—ON SOME RELATIONS OF LIVING THINGS TO THEIR ENVIRONMENT.—The Influence of Locality on Colour in Butterflies and Birds-Sense-perception influenced by Colour of the Integuments- Relations of Insular Plants and Insects—RISE AND PROGRESS OF MODERN VIEWS AS TO THE ANTIQUITY AND ORIGIN OF MAN-Indica- tions of Man's Extreme Antiquity-Antiquity of Intellectual Man- Sculptures on Easter-Island-North American Earthworks—The Great VIII. THE DISTRIBUTION OF ANIMALS AS INDICATING GEOGRAPHICAL Old Opinions on Continental Changes—Theory of Oceanic Islands-Present and Past Distribution of Land and Sea-Zoological Regions—The Palæ- arctic Region-The Ethiopian Region-The Oriental Region--Past changes of the Great Eastern Continent-Regions of the New World—Past His- tory of the American Continents—The Australian Region-Summary TROPICAL NATURE, AND OTHER ESSAYS. . 7 I. THE CLIMATE AND PHYSICAL ASPECTS OF THE EQUATORIAL ZONE. The three Climatal Zones of the Earth- Temperature of the Equatorial Zone --Causes of the Uniform High Temperature near the Equator-Influence of the Heat of the Soil—Influence of the Aqueous Vapour of the Atmosphere--Influence of Winds on the Temperature of the Equator-Heat due to the Condensation of Atmospheric Vapour-General features of the Equatorial Climate-Uniformity of the Equatorial Climate in all parts of the globe-Effects of Vegetation on Climate-Short Twilight of the Equatorial Zone. The aspect of the Equatorial Heavens-Intensity of meteorological phenomena at the Equator-Concluding Remarks. It is difficult for an inhabitant of our temperate land to realize either the sudden and violent contrasts of the arctic seasons or the wonderful uniformity of the equatorial climate. The lengthening or the shortening days, the ever-changing tints of spring, summer, and autumn, succeeded by the leafless boughs of winter, are constantly recurring phenomena which represent to us the established course of nature. At the equator none of these changes occur ; there is a perpetual equinox and B 4, |