XXXV. Photo-chemical researches.—Part IV
The measureless store of energy which Nature has amassed in the sun’s body flows in an unceasing current as solar rays throughout the universe. The labour expended on the earth’s surface in the maintenance of the animal and vegetable creation, and in the production of geological change, is derived, almost exclusively, from this source. Those of the sun’s rays which vibrate most slowly, and form the red portion of the solar spectrum, including the rays visible and invisible which surround them, give rise by their absorption, more especially to the thermic actions observed on the surface of the earth, and in both the fluid zones which as ocean and atmosphere encircle the solid crust of our planet. These rays constitute the sources of heat which, in those grand processes of distillation and atmospheric deposit, have effected those vast transformations of the earth’s crust, by the study of which we obtain some idea of the immensity of the sun’s action exerted during geological ages upon our globe