Solar Energy.

Kaipara and Waitemata Echo, 17 July 1914, Page 8

Solar Energy.

» —- James O. Handy recently gave the following statement before the Engineers' Society of Western Pennsylvania :—-In the tropics, assuming the solar constant at 1800 calories per hour per square metre, it is easily seen that the heat i>er square kilometre will be equal to that produced by the combustion of 1000 tons of coal. A surface of only 10,000 square kilometres receives in i a. year, calculating a day of only j six hours, a quantity of heat cor- j responding to £hat produced by burning 3,500,000 tons of coal, or more than three times the annual production of coal. The desert of Sahara, with its area of 6,000,000 square kilometres, receives daily solar energy equivalent, to 6,000,----000,000 tons of coal. It is estimat- | ed that as a result of the sun's ; rays and the presence of moisture ' and carbon dioxide, etc., in the earth's crust and in the air, the : earth produces yearly 32,000,000,000 ; tons of vegetable matter, when burned, would correspond to 18,000,000 '. tons of coal. Thus the exhaustion j of coal can be prepared for by : studying which types of vegetation : produce woody fibre most rapidly, and we can use intensive and extensive methods of cultivating them, for fuel, and afterwards convert this fuel into energy in the most economic way. There is reason for hope, however, that we may be able Ito do more than to improve agricultural methods of producing fuel if we take advantage of the fact that many chemical changes are pro- ' duced by the action of the sun's rays, and that some of these now known, or which may be discovered, | may be the basis of a method of ' converting the sun's energy in dry, j tropical countries quite directly into a form which may be transmit- ! ted to habitable countries where it may be used.