The great Solar Cone-space, in order to be clearly marked to the eye, was represented in Plate I, page 30, as white. This to some readers may be misleading; as this space when viewed transversely is not luminous,--it is not even visible. (Pl. V.) [Illustration: Pl. V. Solar Cone, Or Cone-Space.] Outside of the atmospheric envelope of all spheres, there is only "_the black of infinite space_."[E] Retro-action between the earth and visible and invisible spheres, gives to the earth the light which it possesses during the night-season. FOOTNOTES: [E] Flammarian. Transcriber's Notes The following typographical corrections have been made: Page x: Heat without combustion--Inter-currents{original had no hyphen; changed to match page 45, to which it refers} Page 60: back and forth to maintain an{comma removed} equilibrium. Page 64: {quotation mark removed}The course of a balloonist Page 102: {quotation mark added}"These clouds sometimes range themselves Page 107: {quotation mark added}"The overwhelming _probability_ of a common cause The following inconsistent hyphenation is as printed: Page 42: just such a retro-acting inter-communication. Page 72: might interfere with the intercommunication of light