SCIENCE SIFTERS.

Auckland Star, Volume XXXVIII, Issue 53, 2 March 1907, Page 10

SCIENCE SIFTERS.

;■ IKDIAN HEMP. \ A single grain of the rosin or Indian hemp will produce catalepsy in a man. A few hours are required for the effects to reach a climax, when his limbs may. be placed in almost any position without difficulty, and when once placed they remain in the given position indefinitely, although the natural influence of gravity would cause them to fall. During the catalepsy the body is usually insensible to .all impressions. NEW WAY TO THE WAVES. For electricity still another use has been found, namely, in the launching of vessels. The British battleshia Agamemnon, recently launched, slid to -the water by ■ this new method. A series of interlocking levers were connected with the electrical' arrangement. The Coun-' tess of Aberdeen, who performed the ceremony, turned a wheel which controlled the apparatus, thus closing the circuit and releasing the triggers that held the man-of-war on either hand. The time occupied by the ceremony was very brief. From the instant the Countess put her hand to the wheel to the ship's clearing the ways was a. matter of but lmin. 50see. EXHAUSTION OP THE WORLD'S MINERAL WEALTH. Many of the necessities of civilised life exist on the earth in limited quantities, and will certainly, give out at no very distant dates. The world's coal will last only a few thousand years, and Britain's only a. few hundred. Most of our best iron has been used up. and we are importing quantities absolutely neeessarv for manufacturing purposes from | foreign, countries.. Leading American authorities . calculate that the immense iron reserves of the United Statee will be exhausted in sixty years; and so it must be with tin and copper, lead, plumbago, petroleum, and a host of other minerals, in the course of a few hundred years. One valuable product of the earth has within the last year or two become perilously dear. The world's known platinum deposits are nearly exhausted, and the metal has to famine prices. Thirty years ago a kilogramme, 2 l-51b., of platinum cost £20; to-day a kilogramme of the crude metal is worth £240, double the price of gold. In chemistry and electricity and many scientific industries this "noble metal," owing to its power as a conductor, its resistance to acids, its small expansion when heated, and non-liability to nist, is invaluable; but wires and terminals, spatulas, capsules, crucibles, and stills of platinum must be sheer luxuries at £100 or £200 sterling per pound avoirdupois. SCARCITY OF PLATINUM. "Make your own platinum," says harsh Nature; "or discover some alloy of commoner metals that shall serve the same purposes." This seems the alternative, and a fortune awaits the man who can find such an alloy. At present we get this rare metal from Russia (the Ural Mountains), Australia, Spain, Oregon, California, and Columbia, accompanied usually with iridium, rhodium, palladium, ruthenium, gold, copper, iron, and osmium, and peradventure there exist in these or other little-known areas, deposits of platinum still to be unearthed. Even now the crust of this old world has been but little probed, and there be. •'treasures "•undreamt*'of »yet-to-be reveal--, cd. We have not the smallest doubt, that a systematic soundmgfof the earth's crust would , payy and that electricity af-. fords the means for making such an examination. LAND ELEVATED BY EARTHQUAKES.

A very distinguished Austrian geologist, Professor Suess, has called in. question the generally received theory of the uplifting of Continents by earthquake forces. The occurrence of raised shorelines and horizontal sheets of marine rocks, is due, he says, to the lowering of sea-level, and not to the raising of the land. Since Playfair's time geologists have held that the level of the land is much less stable than that of the sea. Suess thinks that Darwin and Lyell were in error as to the rise of the South American Pacific coast-line. But .the recent earthquake at Valparaiso leaves evidence decidedly against this view. Professor Curtis, of the Lick Observatory, Santiago, after a careful investigation, finds the harbour of Valparaiso 10ft shallower than it was before August 16, 1906. The land movement was mainly vertical. Even this remarkable rise is trifling compared with that caused by the Alaska' earthquake in 1889. Messrs. Tarr and-Martin, American geologists, have shown that for more than 100 miles the whole Yakutat coast, in Alaska, was lifted upwards, the the maximum elevation being in Disenchantment Bay, where the land was raised 47ft 4in. "Elevations of 7ft to 20ft were common. "J. M." which, we suspect stands for Professor John Milne, writes to "Nature" that the quake investigated by Messrs. Tarr and Martin is probably represented by the movement of one or two millions of cubic miles of rock material, and there are some sixty world-shaking movements of this kind every year. HAS THE MOON AN ATMOSPHERE? It is an unsettled question in astronomy whether there is any trace of an atmosphere on the moon. Most of the evidence is against that supposition; but Professor W. H. Pickering believes that the white epot near the crater lanne on the lunar surface 'is snow or hoar frost. A German astronomer, Dr. Wirtz, writes to the "Astronomisehe Nachrichten" that he had produced an apparent enlargement of the white spot by interposing a shade-glass between the telescope and the eye, and thence he argues that the enlargement of the white spot during an eclipse of the moon— when, of course, the sun's heat is cut off —is a subjective phenomenon due to the diminution of light. Professor Pickering raises several objections to this explanation, chief of which is that the enlarged spot remains after re-illumination of the moon's face. The subject is a difficult one. Like the supposed canals of Mars, no two observers see alike. As we are always looking at the same side of the moon, and as its solar disc lasts for a whole fortnight, it might be expected that the appearance would be more general than has been indicated.

Two notable achievements in wireless telegraphy are reported by "Engineering." Messages were sent from Nauen, Germany, to steamers. 1500 and 1300 miles away.