THE SUNS ENERGY.

New Zealand Graphic, Volume VIII, Issue 49, 5 December 1891, Page 655

THE SUNS ENERGY.

Whatever one eats, the material of which goes to compose the body, is made to grow by the light and heat of the sun. Upon its effulgence the plants depend for their development, and upon things vegetable all animals must rely for food. Thus it may be said that every man or woman represents a certain quantity of stored solar energy. The force of gravitation constantly summons attention, because the whole scheme of existence depends upon it, but, while the power that pulls things down is so evident, how many people ever consider the mysterious potency of the sunbeams to lift things up ? It is not the soil that upraises the plant. Phuebus, as the ancients called him, builds up all the trees of the forest. Not only does he set one par tide of matter on top of another in the process of construction, but in each tree he locks up a store of energy thousands of times greater than that which was expended in merely erecting the trunk. This may be seen when the energy is unlocked by burning the tree under the boiler of an engine, which will produce power enough to raise thousands of logs equally big. The monarch of the woods may fall and turn to coal in the soil, though still keeping imprisoned within its four millions of years the energy which ages afterwards may be liberated to run a printing press or other machine. This newspaper itself is printed by sunbeams which fell upon the earth ever so many centuries before man was first born. The paper upon which these words are marked was made from materials grown by the sun. The human race is maintaining existence by keeping itself warm at this great fire of the sun. When it goes out mankind will vanish also. The question is, therefore, of absorbing interest how long the combustion has lasted, for what length of time it will continue to endure, and of what nature it is ’

Respecting its intensity, many comparisons might serve for the purpose of conveying a vivid notion to the mind. For example, suppose that all the ice and snow at the Arctic and Antarctic poles could be swept together and a tower made of the material fifteen miles in diameter. Imigine that it could be preserved untouched by melting while the accumulations of successive winters were heaped upon it until it should be 240,000 miles high and stretching to the moon. Then conceive that there should be concentrated upon it the sun’s entire heat for one second. In that brief time the whole would be gone—melted, boiled and dissipated in vapour.

How is this heat maintained ? It is readily proved that if the sun itself were one solid block of coal it would burn out altogether within a few centuries. But it is known absolutely that during historic times there has been no noticeable diminution of the sun’s heat, for the olive and the vine grow just as they did and where they did 5000 years ago. Thus it is evident that the process concerned is not one of ordinary burning. Only one theory would account for the phenomenon, and that is unquestionably the true one, namely, that the sun’s own slow contraction develops the heat it gives out. Of course, there must be an ultimate limit to the shrinking of that wondrous sphere of filming gas, and science, looking into the future, declares that the heat supply is enough to last four or five million years longer before it sensibly fails. Within 10,000,000 years it will have ceased

to give out any warmth wot th mentioning, but before that period arrives man will have discontinued his interest in the subject, inasmuch as he will long previously have passed oil the face of the earth, which will then be reduced to the condition of a dead planet like the moon. Obviously, it is. possible that some wandering star may fall into the sun, and in this way restore the wasted energy of ages by the collision, but such an event seems hardly likely. A very striking illustration of the power of the sun's lays is afforded by a simple lens used as a burning glass. No very great burning lens has been constructed for a long time. During the last century an enormous one was made in France, all the heat falling upon it being concentrated upon a smaller one, and the smaller concentrating it in turn, until at the very focus it is said that iron, gold and other metals ran like melted butter. In England the biggest burning glass on record was made about the same time for the British Government, which designed it as a present for the Emperor of China. It was three feet in diameter, and beneath it even the diamond was reduced to vapour. The Emperor, w hen he got his lens, was much alarmed lest, possibly it was sent by the English for the purpose of injuring him. By way of a test a smith was ordered to strike it with his hammer, but the hammer rebounded front the solid glass, and this was taken to be conclusive evidence of magic in the thing, which was immediately buried, and probably is still reposing under the soilofthe Celestial Kingdom. Many attempts have been made to utilise the sun’s rays for running machinery. The idea ought to be in some way practicable, inasmuch as every square yard of earth receives enough energy in the shape of sunbeams to represent one-horse power. Even on such a small area as fifty square miles the noontide heat is enough, could it all be utilised, to drive all the steam engines in the world. Sun machines have already been made to go, though not successfully as yet from the economical point of view. However, the day is not unlikely to arrive before long when the thing will be done, and the orb of day fairly harnessed for working all the engines on the earth.

Make friends with your creditors, if you can, but never make a creditor of your friend.