THE SUN’S HEAT.

South Canterbury Times, Issue 2848, 11 May 1882, Page 2

THE SUN’S HEAT.

[to the editor.]

Sir,— Can you spare room for a few lines iu reply to ‘‘Amateur’s” second letter, in which he still clings to his idea that the sun does not radiate heat ? At first ho seemed to regard it as a source of electric currents which kindles heat on reaching our atmosphere —now he thinks the sun is electric light itself, and therefore devoid of beat. But whilst electric light, such as is coming into use, is relatively, cool (as compared with gas or kerosene), it is a fact that the temperature of the electric spark is so high tliat it exceeds that of an oxy-hydrogen flame. The rays of an electric lamp concentrated to a focus by a mirror, will kindle gunpowder, or light a cigar. “Amateur” also speaks of light as being the result of motion, which is, so far, quite correct, hut it is also true that motion never takes place without heat. Mechanical motion never does, and I believe the same applies to chemical action. If you say then that light is the result of motion, yon imply that light is also the result of heat, for heat is first developed by motion, and thus heat is a source of light.—l am, &c., H.W.H. Tmiaru, May 10.