Science.

Alexandra Herald and Central Otago Gazette, Issue 349, 15 January 1903, Page 7

Science.

DECREASE OF THE TSETSE FLY. §'V is well known that many parts of Africa are closed to the explorer in consequence of the existence of the dreaded tsetse fly, whose bite is fatal to animals: It has long been suspected by African travellers that this terrible South I African scourge draws its poison from the dead, bodies of wild animals. This" theory is now strongly supported by M. Foa, the French explorer. He proves that in the Transvaal the tsetse is no longer a pest, presumably owing to the almost complete extinction of wild carnivorous animals. On the contrary, in the region of the Zambesi, where wild elephants and other animals die and putrefy, the tsetse is still a plague. MICfiOBES HELP MAKE CHEESE. Perhaps there is no better illustration of the utilization of bacteria that is to be found in advanced methods of treating common dairy products. Ten years ago if a dairyman had that he actually employed micro-organisms to aid him in making butter and cheese ha would have been boycotted and forced out of business. But to-day it is d'ffaront, for dairy methods have been almost revolutionised by the discoveries of modern bacteriologists. In the first place it has been conclusively shown tbat the souring of milk is always produced by bacteria and that the popular belief that thunderstorms will perform the same Sanction is"erroneous. ; It also has been proved that bacteria produce slimy milk, bitiirr milk, blue milk, yellow milk, green milk, orange coloured milk, amber coloured milk, chocolate milk and even black milk. - .

CURE FOB CATARACT, A French oculist has taken up with remarkable success,.-the, treatment of cataract without 'operation by| the application of baths of salicylate- of soda. He has arrested the progress of the opacity o! crystalline lens of several years in numerous cases and is sanguine of success if the treatment is begun at an early stage. GAS £2OO PER CUBIC FOOT. That rare element helion, which was found first in the sun by the spectroscope, and then by Professor Ramsay in the. mineral elevite, is the costliest substance known. It has basn fouad recently in the ga3es*givea out by the hot springs at Batb, ; and* Professor Dewar is collecting it*to £i|hnut the element to his. his-h pressures ana'loV 1 temperatures. It costs £2OO per cubic foot to collect, or mora;. than a million times the price of coal gas. To freeze it enormous pressure and almost the absolute zero of heat will be needed. The process is- difficult and rather dangerous, and the Professor and his assistants at the Royal Institution require jto exercise the utmost care, for the eacap?* of only fire feet;of the gas would mean £I,OOO gone irretrievably.

LIGHT DISCOLOUR 3 GEMS. The discoloration of precious stones when they have been .exposed to the air for a long time-is-well known. Emeralds, rubies and sapphires are less susceptible to atmospheric influence, but even they, says the * Tatler.' are not exempt from change, If two rubies of the same size and shade are kept for, say two years, one in a showcase and the,' other in absolute darkness, an examination of the stones at the end of that time will invariably show that the showcase ruby has become distinctly light in colour; The most'sensitive of all stones t > variations in light is the opal. This stone draws its marvellous rainbow reflections from numerous little clefts, which allow the light to pass and reflect it in different directions. Often the opal stands the' manipulations of cutting . and polishing well, and all of a sudden it splits. ■.'.'."

BLOCKS OF CARBON. IN LUNGS. The lungs of a polisher of electric light carbon terminals were exhibited by M. Lancereaux at a recent meeting of the French Academy of Medicine, and it was shown that the said organ had been transformed into veritable blocks of carbon. Yp to the age of thirty-six the deceased bad been a robust-stonemason',, but was, then : transferred* to a workshop eight metres long by seven broad, where, with eight other men, he was engaged in polishing on! Btone mills carbons for electric lighting. The ; shop was so badly ventilated that sometimes they could not distinguish teach; other the stone, dust, and charcoal> filling the atmosphere, and the result was apparent in M. Lancereaux's exhibit, which was strong argument, if one was needed,, for the better vtntilation of workrooms and the use of the respirator. . 'A •

■ WHAT MOULDS THE PACE. ,It | appears probable that the tailor's distinctive ~ type of face may have boen partially created by his habit of working hw jaws with his shears. Let any ojie /tpatoh a parson cutting a piece of tolfgh, material with scissors, and he wiltseej that the lower part of the face wags in rhymetie'and spontaneous unison with the blades. Shepherds and farm labourers who join sheep-shearing ganga certainly acquire .a different expression while engaged in this kind of work. The cast of countenance by which one so easily recognises a groom is partially ex ■< plicable by the fact that the muscles which close the ja ,f and compress the lips are always called into jplay when we are assertihg' our 1 will over that of a horse. Nearly all jockeys and other horsey men have a peculiar set of the mouth and chm> although no special characteristic about'the ;-eyo ;or j;he upper part of the ?ace izt&Y Bedistinguishable.'' It is instructive to compare the visage of the ruler of horses with f at of the ruler of men'. The" horseman's face shows com-' mand in the mouthy the drill sergeant's in; the mouth and the eye. The last is undoubtedly the most effective instrument in exacting obedience from our own species. •• '"■"-■■ ; - '-■■ J •