STUDY OF MARS.

Manawatu Herald, Volume XLIII, Issue 2327, 10 September 1921, Page 1

STUDY OF MARS.

A MILLIONAIRE’S HOBBY,

FIFTY-FEET MERCURY MIRROR

Utilising Cluinaral, Chili, as an obervation station, Mr. B. M'Afee, the American millionaire scientist and Professor Todd, of Harvard University, intend in 1924 to study Mars, to determine whether human life exists on the planet, and whether intelligent work is done there. An enormous telescope is at present being constructed. Mr. M'Afee has dispensed with the glass mirror and substituted an invention of his own —a flat dish, fifty feet in diameter, containing mercury. The dish will be rotated at a certain speed, and the surface of the mercury will become concave, and form a splendid mirror. The total magnification will be twenty-five millions, so that the surface of Mars, thirty-five million miles away, will be brought to within one mile and ahalf of the observers. During 1924 Mars will, on three occasions, be nearer the earth than for a century.

[The largest telescope in the world is the 100-inch Hooker reflector, at Mount Wilson Observatory, California. The principal portion of a “reflector” is a mirror, nowadays made of glass silvered on the front surface, hut formerly made of “speculum metal.” This mirror is carefully ground slightly hollow, the

cuiwcof the surface being a parabola. The larger the mirror is, the more difficult it becomes to grind it accurately, and the difficulty of mounting it so that it is not pulled out of shape by its own weight increases with size even more seriously. The idea of using a rotating basin of mercury as a parabolic mirror is not new; but any means for revolving a large vessel at absolutely constant speed and without tremors, which would at once destroy the “figure” of the reflector, will be a novelty. The mercury mirror will, of course, be horizontal, and can only work with light falling upon it vertically, but that can be arranged by means of plane reflectors, so that'any position of the sky can be observed. When Mr M’Afee has built his dish, and filled it with

about fifty tons of mercury—making a film less than an inch thick — and has made a mechanism to turn it round, he will have to selve another problem, at least as difficult — that of making a plane mirror more than fifty feet in diameter, and mounting it so that it will not be distorted, and yet can be swung in any position, and kepi in smooth motion for the following of the planet under observation.]