ABSTRACT
The flood of solar energy is so enormous compared with our need that somehow, one tends to feel, it should be possible to direct an adequate trickle of it into forms that would power our comparatively puny human industries. In ground plants, the chemical energy accumulates for several months; in trees, it accumulates for many years. It is just because the chemical energy accumulates for much longer in trees than it does in ground plants that the peoples prefer to burn wood as a fuel rather than, say, straw. The energy stored in straw, wood, coal, oil, and gas is all chemical; they are all for the most part of the same nature, all hydrocarbons. Engineering systems for these energy sources are well-developed, probably with little that is radically new to be added. The rain, and the snow when it melts, then runs downhill, turning energy of position into energy of motion.
