8. Gravitation could, under no possible condition, have generated the Amount of Heat required by the Nebular Hypothesis 27 9. Condensation the Third and last stage of a Nebula 30 10. How Nebulæ emit such feeble Light 30 VI. Binary Systems 32 VII. Sudden Outbursts of Stars 33 VIII. Star Clusters 34 IX. Age of the Sun’s Heat: a Crucial Test 34 PART II. _EVIDENCE IN SUPPORT OF THE THEORY FROM THE AGE OF THE SUN’S HEAT._ TESTIMONY OF GEOLOGY AND BIOLOGY AS TO THE AGE OF THE SUN’S HEAT 37 Testimony of Geology: Method employed 39 The Average Rate of Denudation in the Past probably not much greater than at the Present 44 How the Method has been applied 47 Method as applied by Professor Haughton 50 Method as applied by Mr. Alfred R. Wallace 51 Method as applied directly 52 Evidence from “faults” 53 Time required to effect the foregoing amount of Denudation 62 Age of the Earth as determined by the Date of the Glacial Epoch 64 Testimony of Biology 65 PART III. _EVIDENCE IN SUPPORT OF THE THEORY FROM THE PRE-NEBULAR CONDITION OF THE UNIVERSE._ Professor A. Winchell on the pre-nebular condition of matter 71 Mr. Charles Morris on the pre-nebular condition of matter 75 Sir William R. Grove on the pre-nebular condition of matter 78 Evolution of the Chemical Elements, and its Relations to Stellar Evolution 80 Sir Benjamin Brodie on the pre-nebular condition of matter 84 Dr. T. Sterry Hunt on the pre-nebular condition of matter 85 Professor Oliver Lodge on the pre-nebular condition of matter 87 Mr. William Crookes on the pre-nebular condition of matter 90 Professor F. W. Clarke on the pre-nebular condition of matter 98 Dr. G. Johnstone Stoney on the pre-nebular condition of matter 99 THE IMPACT THEORY IN RELATION TO THE FOREGOING THEORIES OF THE PRE-NEBULAR CONDITION OF MATTER 102 The Theories do not account for the Motion of the Stars 105