MORE USE OF THE SUN.

Ashburton Guardian, Volume XXIX, Issue 7817, 9 June 1909, Page 1

MORE USE OF THE SUN.

■When the world grows colder the^ white' races will' probably cluster for food and: warmth nearer the equatori m regions expurgated of tropical diseases by sanitary • science ; but before' that' times comes the world's engineers, if they do'not have to construct Martian canals or earth-crust borings to the. lnternai heat of the globe, will have had leisure to discover new means of Utilising the abundant and wasted energy lavished on us; by the sun. Solar mirrors with concave multi-sur-; faces have been tried,, but the results have '■ not been very satisfactory ;.' nor have those more lately tried, m which an attempt was made to work a small engine by the heat which a sort of extensive 'series, of cucumber frames collected from-the sun's rays. The problem has ': been . considered from another 1 point of ■■■ view by Professor Wood, who throws doubt on the accepted theory as to the mode m which; a greenhouse warms up under the action of. the sun's rays. It is usually, thought that ■ the heating is due to glass . being transparent to light, butimperyioui to dark''radiation. The luminious rays from the sun pass easi-ly-through the glass ; being absorbed by the plants and soil, they are transmuted r'into idark radiation which cannot escape through the vglass \ hence there is. an accumulation of heat energy inside. Professor Wood, is- 1 inclined, on the.other.hand; to attribute the warming to heating; by contact of the air with.'the ground;warmed bjrthe sun';' Owing ' to. this warming by vcrfn-. tact, convection currents are set up which continually distribute the heat throughout "the"limited amount of air enclosed m the house, which, therefore,'quickly rises m temperature. •'