CHAPTER I. The Length of the Year 28

II. The Length of the Day 37 III. The Mass of the Earth 43 IV. The Magnitude of the Ocean 50 V. The Magnitude of the Atmosphere 51 VI. The Constancy and Variety of Climates 52 VII. The Variety of Organization corresponding to the Variety of Climate 57 VIII. The Constituents of Climate 66 The Laws of Heat with respect to the Earth 67 IX. The Laws of Heat with respect to Water 70 X. The Laws of Heat with respect to Air 81 XI. The Laws of Electricity 91 XII. The Laws of Magnetism 93 XIII. The Properties of Light with regard to Vegetation 94 XIV. Sound 96 XV. The Atmosphere 102 XVI. Light 104 XVII. The Ether 111 XVIII. Recapitulation 113