SUNLIGHT. _Its Source and Nature._ Sunlight is one of the products of that grand retro-action which is incessantly in operation between sun and earth, and is, in its intimate and essential nature, a vito-magnetic _fluid_[B] (or so-called magnetic). Subtle, and apparently intangible, manifesting itself rather as a presence than a real substance, it fills all the space between the sun and earth--which space may, with sufficient accuracy, be termed the solar cone or cone-space. _Its Limits._ Beyond the boundaries of the solar cone, _no light is_. [Illustration: Pl. I. SOLAR CONE.] _The Sun not Incandescent._ The apparent brightness of the sun is owing to the aggregation of the 93,000,000 of miles of this fluid which is present between the sun and earth, or to our presence in the great current of activity of the vito-magnetic force. It is therefore not due to a condition of incandescence _at_ or _near_ that body. It is cool and habitable, and emits no light. The brightness of the intervening fluid intercepts the view, and thus no one may behold its body. Dark spots upon its face disclose its true character.[5] If, therefore, the sun be truly dark, the brightness of its satellites cannot be caused by light projected from its surface or surroundings. How, then, may we account for the light of the moon and planets, which do not possess a light _sui generis_? A new hypothesis is requisite. To frame this hypothesis is not difficult. _The New Hypothesis._ Analogy teaches us that the earth is seen from the moon and planets, even as they are seen from the earth. Yet there is nothing upon the face of the whole earth which is capable of reflecting the slightest amount of the sun's rays to those spheres. The fields, forests, rocks, and seas, only absorb light, they do not reflect it. In this phenomenon, therefore, there is no element of specular reflection. It consists rather of the lighting up of the static vito-magnetic fluid of our atmosphere, by the great solar current. The atmosphere, thus vivified, discloses our presence to those orbs, and in like manner, their presence to the inhabitants of the earth. _No Borrowed Light._ The light of the planets is therefore in no sense a borrowed light, since the action which generates and transmits it, is purely co-operative. Otherwise there could be no light at the earth, or planets. _The Sun Dependent for His own Supply._ And, indeed, the sun possesses within himself alone no element of supply of his own needed light and heat; and in his immensity and power is even _dependent_ upon the circling orbs, for the quantity of each which is indispensable to a condition of habitation.