PHYSICAL GEOGRAPHY or PHYSIOGRAPHY treats of the conformation of the earth’s surface, of the distribution of land and water, of minerals, plants, animals, etc., and applies the principles of physics to the explanation of the diversities of climate, productions, etc.
POLITICAL GEOGRAPHY treats of the different countries into which the earth is divided with regard to political and social institutions and conditions.
=Geology= (_jē-ŏl´o-jy̆_).--The science which treats: (a) Of the structure and mineral constitution of the globe; structural geology. (b) Of its history as regards rocks, minerals, rivers, valleys, mountains, climates, life, etc.; historical geology. (c) Of the causes and methods by which its structure, features, changes, and conditions have been produced; dynamical geology.
=Goniatites= (_gō-ni-a-tī´tēz_).--Fossil remains of Ammonites, many species of which are found in Devonian and Carboniferous Limestone.
=Hail= (_hāl_).--Frozen rain, or particles of ice precipitated from the clouds, where they are formed by the congelation of vapor. The separate particles are called hailstones.
=Harmattan= (_här-măt´tan_).--A dry, hot wind, prevailing on the Atlantic coast of Africa, in December, January, and February, blowing from the interior or Sahara. It is usually accompanied by a haze which obscures the sun.
=Hoarfrost= (_hōr´frŏst_).--The white particles formed by the congelation of dew; white frost.
=Hydrography= (_hī-drŏg´rȧ-fy̆_).--The art of measuring and describing the sea, lakes, rivers, and other waters, with their phenomena.
=Hygrometer= (_hī-grŏm´ê-tẽr_).--An instrument for measuring the degree of moisture of the atmosphere.
=Ignis fatuus= (_ĭg´-nĭs făt´ûŭs_).--A phosphorescent light that appears, in the night, over marshy grounds, supposed to be occasioned by the decomposition of animal or vegetable substances, or by some inflammable gas,--popularly called also Will-with-the-wisp, or Will-o’-the-wisp, and Jack-with-a-lantern, or Jack-o’-lantern.
=Ichthyosaurus= (_ĭk-thē-ō-saw´rus_).--A large marine reptile, known only by fossil vertebræ and other bones, found in oolite rocks.
=Labyrinthodon= (_lab-i-rin´thō-don_), or Mastodon. A large animal, belonging to Amphibia, remains of which are found in Upper Trias rocks and strata.