SOLAR ENERGY.

Taranaki Daily News, Volume LIII, Issue 258, 10 March 1911, Page 7

SOLAR ENERGY.

.POWER FOR WORLD'S WORK. It was recently cabled that Sir J. J. Thomson, Cavendish Professor at Cambridge University, had said that the sun transmits power on a clear day equivalent to 7000 horse-power per "acre. If it could be harnessed all the power required for the world's work would be obtained at a cost of lowering the tern perature a degree or two. Sir J. J. Thomson is one of the ino»i distinguished of living English scientists. He was one of those who predicted the .behaviour of radium and wa» granted the Nobel prize for physics in lOOti. As President of the British Asso ciation for the Advancement of Science in 190!) he dealt at some length with the question of harnessing the sun. Speaking of the untapped energv derived from the sun he stated that according to the measurements of Langley, under a high sun and clear sky the heat derived from the sun is equivalent to about 7000 horsepower per acre, and though this is not utilised at present he had not the slightest doubt that utlimately it would be. Then when coal is exhausted and oui water-power is inadequate it might be that the centres of industrial activity would be transferred to the burning deserts of the Sahara, where the sunbeams could he tapped better. The ether which seems theoretical, Sir Joseph continued, is really the medium through which all the benefits of the sun come to us. It is very probably of about 2000 million times greater density than lead, and lest.it should seem inconceivable that we are surrounded bv such a medium the lecturer pointed out that all matter is probably composed mainly of holes. SOURCE OF THE SUN'S HEAT. As regards the much-discussed question of the source of the sun's heat Mr. Hector Macphersou, in his book on Astronomy in ]!)08, states :

It has been calculated that if the sun were composed of coal it would hist foi only six thousand years. Now, we know that the sun has lasted for a much longer period, and that ■ there are no signs of its decline. There must, therefore, be some mechanism by which the sun's heat is maintained. It was sti"gested by the late Lord Kelvin that numbers of meteors falling into it might effect this purpose;- but, as has been pointed out by Sir Robert Ball, supposing the moon, for instance, were crushed, into fragernents and allowed to fall on the sun's surface, the heat caused by these fragments would be exausted in a year. Thus another theory must be formed. It has been found that the sun is continually shrinking in size, so that it actuallv contracts sixteen inches every day. By this contraction heat is generated which will keep (lie sun at a lu'glr I temperature for ten million years. -After that it will become a cold,' dark globe. An element of uncertainty, however, has been introduced into these calculations by the discovery of radium. In radium. it has been suggested, there may ho an-' other source of energv, which may alter the estimate. On this point, however, there is no unanimity of opinion. Tt is well to bear in mind that the inhabitants of this planet only receives a small fraction of the sun's heat. Mr. H. R. Mill, in his book, ''The Realm of Nature," .rives the following admirable illustration of the earth's share of the solar heat: "If the sun were expending, instead of energy, money at the rate of £IB,OOO- - a year, the earth's annuity would only be .CO."