THE SUN'S SUPPLY.

Tuapeka Times, Volume XVIII, Issue 1122, 25 February 1885, Page 4

THE SUN'S SUPPLY.

From an article on "The Sun's Energy" by S. P. Langly, in the December number of the " Century," we quote the following :— " How is this best maintained ? Not by a miracle of perpetual, self-sustained flame, we may be sure. But, then, by what fuel is Buch a fire fed ?■ There can be no question of simple burning, like that of coal in a grate, for there is no source of supply adequate to the demand. The State of Pennsylvania, for instance, is underlaid by one of the richest coalfields of the world, capable of supplying the whole country, at its present rate, for more than a thousand years to come. If the source of the solar heat (whatever it is) were withdrawn, and we were euabled to carry this coal there and shoot it into the e>olar furnace fast enough to keep up the known heat supply, so that the solar radiation vould go on at just its actual rate, the time which this coal would last is easily calculable. It would not last days or hours, but the whole of the coal would be used up in rather less than one-thousandth of a second. We find by a similar calculation that if the sun itself were one solid block of coal, it would have burned out to the last cinder in less time than man has certainly been on the earth. B"t during historic times there has as surely been no noticeable diminution of the sun's heat, for the olive and tbe vine grow just as they did three thousand years ago and therefore the hypothesis of an actual burning becomes untenable. It has been supposed by some that meteors striking the solar surface might generate heat by their impact, just as a cannon ball fired against an armour plate causes a flash of light and a heat so sudden and intense as to partly melt the ball at the instant of concussion. This is probably the whole source of heat supply, as far as it goes, but it cannot go very far ; and indeed, if our whole world should fall upon the solar surface like an immense projectile, gathering speed as it fell, and finally striking (as it would) with the force due to a rate of over three hundred miles a second, the heat developed would supply the sun for but little more than sixty years."