WIZARDS DEMONSTRATE

Evening Post, Volume CVI, Issue 15, 18 July 1923, Page 3

WIZARDS DEMONSTRATE

A "MOHAMMED'S COFFIN"

EXPERIMENT IN MAGNETISM,

The annual conversazione of the Royal Society was held recently at Burlington House, London, says a correspondent of' the ".\lanchester Guardian,"' and a programme of very varied interest was provided. "Unquestionably the most striking event was the demonstration by Mr. AVal.ter Heane of a series of kinematoKraph pictures of the action of explosives and projectiles. His pictures were taken at rates of the order of 50C0 to the second, and he was able to demonstrate the exact way in which a glass plat was shattered "when a bullet' pierced it, and had a solid rubber ball, behaved when shot at a portion of ar-mour-plating. The ball was propelled by a wooden plunger, and this could clearly be seen twice hitting the ball before tho latter attained its maximum speed. Several seconds were taken for the ball to cross the cinema field, and each phase of the ball's deformation could be clearly made out.

The lecturer also showed gxactlv what occurred when a glass bowl containing water was shattered either by a projectile or by an explosion generated inside the flask. Biology this year is.well represented. Sir Richard Paget in a set lecture by means of plasticine models demonstrated exactly what occurs when the English vowel sounds are pronounced. A CROCODILE'S VICTIMS.

The zoological department of the British Museum had on show a rather terrible exhibit of the contents of a maneating crocodile's stomach. The stomach contained a dozen heavy metal bracelets, .all ■ obviously belonging to victims that ho had devoured, a necklace (clearly absorbed shortly before capture, as the strincr holding the beads together was still intact), shields of a tortoise, and quills of a porcupine.

Another biological exhibit of special interest was that of Mr. H. Graham Cannon, who had three beetles operated on by one of Przibram's pupils, in which the original heads had been removed, and others grafted in their place. One specimen was specially dissected out to show the complete way in which the gullet of the original beetle had joined up with the gullet of the added head. From the behaviour of the.beetles it appeared that sex inclinations were dictated by the new head implanted, and also certain colour variations. ■

Rothamsted was showing an ingenious and complicated electrical machine that makes it possible very easily to judge between good tilth and bad tilth. The apparatus works as a complete automaton and tells tho student whether the soil is in the condition . that a sculptor would degire for modelline clay (with its particles separated like, football players comins on 'to the plavinc grounds) or in the condition suitable for culture (like football teams in action and in scinm formation).

A HESITATING MAGNET: ; I From the standpoint of wizardry, the most sensational exhibit is what can be i best described as the Mohammed's co.tin experiment, though.catalogued by Mr. JF. Harrison , Glew as "a hesitating magnet." Mr. Glew showed an . ordinary magnet that held floating by repulsion above it -a bar magnet of cobalt .steel which could be made to approach to or recede from the ordinary magnet, .but that roinained floating unsupported inair. controlled merely by guides, that prevented it from turning out to tlie poles of the magnet's axis. The experiment deponds on the nature of the cobalt steel; an ordinary magnetic material would be unduly influenced by the magriet. t ... . ■ ■

A new form of an old experiment was shown by Professor MacGrogor-Morris and Mr. E. Mallett, who demonstrated by means of sand thrown on a telephone receiver the nature of the vibrations set up under tho influence of electricallyproduced sound waves. Seven clearlydefined forms of vibration, all audible, were strikingly illustrated.'

Professor H. C. K. Carpenter had an exhibit of a series of large aluminium crystals that' had been subjected to strain. AVhen the breaking-point was reached the fracture occurred invariably in the crystal itself, some six to eight inches"in longth, and never at the junction between two cystals, the, joining proving stronger than the crystal itself. Mr. Conrad Beck had a number of microscope's on view with the idea that by the use of polarisod light glare in tha microscope field could .be avoided. His specimens were, of singular beauty. The same can •be said of Mr. K. Traveri'or's •stereo-photo-michographs of water mites in natural colours.

The exhibits' of th 0 NationaLPhysicnl. Laboratory made an appeal to the expert rather than to the public,■■ wftK the ex-, ception of sections of a wood known as balsa .wood. This wood is very lisht. and contains a large number of rigidlvdivided air cells, with the result that "it acts as a non-conductor of heat, and may prove of. gre.it value in connection- with the transport of foodstuffs.

TELLING THE HERRING'S AGE.

Mr. Buchanan-AVollaston had •an exhibit of a number of specimens of herring scales. The.attempt has been made to determine the ago of the herring by the rings on its scales, much in the same way that the age of a tree can be determined by its ring markings. The parallel-, however, has been, shown not to be exact,,and herrings are now going to. be captured, marked, and released in the hope of learning more of their general,life history. ' ■

Human well-being was most notably represented by Dr. E. H,' J. Shuster's katathermometer. Observers have shown that the comfort of a worker depends very largely on the cooling power of the air, and Dr. Shuster's instrument enables this to be determined automatically and with absolute accuracy, and to be recorded over an indefinite period. With this should be compared the instrument shown by Dr. Leonard Hill and A. Eidonow for studying the effect of. temperature on the biological action of light, a demonstration that may have considerable influence on the light treatment of tuberculosis.