The simplicity of the zonal distribution of solar energy on the earth's surface, which would characterize a uniform globe, is entirely destroyed by the dissimilar action of land and water with regard to radiant heat, and by the influence of crust-forms on the direction of the resulting circulation.
The investigation of this substance and its properties (see Radioactivity) has proceeded so far as to render it probable that the theory of the unalterability of elements, and also the hitherto accepted explanations of various celestial phenomena - the source of solar energy and the appearances of the tails of comets - may require recasting.
If these two advances could be combined, we would have a supply of solar energy that was cheap, abundant, and environmentally benign.
It merges into physical geography, which takes account of the forms of the lithosphere (geomorphology), and also of the distribution of the hydrosphere and the rearrangements resulting from the workings of solar energy throughout the hydrosphere and atmosphere (oceanography and climatology).
Brown and Escombe have shown that the amount of solar energy taken up by a green leaf may often be fifty times as much as it can utilize in the constructive processes of which it is the seat.
To deal in generalities, plants capture, on average, about 5 percent of the solar energy that falls on their leaves.