SCIENCE NOTES.

Otago Witness, Issue 2928, 27 April 1910, Page 76

SCIENCE NOTES.

—Artificially Rolling a Ship.— It would seem to the ordinary observer that a 16.000-ton, •■* even smaller, battJesnip would be ton huge to be made to -oil by the assembled movement of the screw from side to side, vet it seems the simplest matter ii> the . world to cause an artificial roll of from sdeg to lOdeg in this manner. It is called "sallying ship," and is now a common occurrence on the American worships, since the new target practice regulations specify that firing must take place while the ship is rolling. If the sea is not rough enough to cause the ship to roll the required -number of degrees, the crew is lined up on the side of the deck, and at a signal blown on a bugle run oyer to the other side.—Popular Science Sittings. —Airships and Wireless Signals.— 'A system of wireless signalling for airships has been invented by Dr Friednoh Lux The idea of the inventor is that all airships should be equipped with a receiving apparatus which will weigh only bib, and that wireless signalling stations should be equipped all over the country at about 50 kilometres apart. At intervals of five minutes these signal stations should send out wireless messages by which they could be identified and aviators informed of their whereabouts. A combination of a few letters would, it is suggested, be sufficient to distinguish one station, from another, and by the increasing or decreasing strength of the electric -'mpulse the aviator could fcell whether he was approaching or receding from a- particular station. —Does Electricity Prolong Life?— London Dailv Mail prints an interesting 'despatch from Paris. It states that two doctors of that city-Professor d Arsonval and Dr Montier— claim to have discovered a method of prolonging life. Briefly, thentheory is that the decay of the arteries, from ■which all death and disease spring, may be prevented and cured by an electric current Professor d'Arsonval has invented a. machine of extremely high power, with which he has already experimented on patients—among others, M. Jean d Orsay, who wrote in enthusiastic terms .about it in the Matin. M. d'Orsay describes the treatment as cleansing all the arteries and other organs, and restoring them to their original elasticity and health. "There is no longer,", he states, "any esential reason Why we°should grow old. or even die." —An Interesting Comparison. — The time which has elapsed since the first prapearanoe of life on our earth has been variously estimated at 100,000,000 to 200,000,000 years. To tax our powers of comprehension as little as possible Dr H. Schmidt, of Jena (Germany), has taken the Shortest estimate, and has tried t< make understandable the five great evolutionary periods through which life has passed by comparing them with a day of 24 hours. This is the result:—The Archeozoic period (52,000,000 years) is represented by 12 hours 30 minutes; Paleozic ,(34,000,000 .years), 8 hours 7 minutes; Mesozic (11,000,000 years), 2 hours 38 minutes; Cenozic (3.000,000 years), *3 minutes; Anthropozoic (100,000 years), 2 minutes. If the last period, the aged man, be comipared in its subdivisions by the" same scale, it is found that the "historic" portion covers only five seconds, and two seconds are sufficient for the Chris tian era. —The Siberian Snow Flower. — The latest p.lant wonder is the snow flower, reported to have been discovered by Count Anthoskoff in the most northern portions of Siberia, where the ground M continually covered with frost. This wonderful object shoots out from the frozen soil only on the first day of each -uicceeding vear. It shines but for a single day. and "then resolves to its original elements. The leaves are three in lumber, and each about three inches in diameter. They are developed only on that sidle of the stem towards the north, and each seems covered with microscopic crystals of snow. The flower, when it opens, is star-shaped, its petals of the same length as th» leaves, «nd about half an inch in width. On the third day the extremities of the anthers, which are five in number, show minute glistening specks like diamonds, about the size of a pin's head, which are the seeds of bhis wonderful flower. —A New Nickel Alloy.— Monel metal, a new alloy of nickel .recently out on the market, contains 68 per cent, of nickel, 1.5 per cent, of iron, and 30.5 per cent, of copper. It is silver-white, and takes a brilliant finish, which it retains indefinitely. It is said to possess a tensile strength about 25 per cent, greater . and an elastic limit about 50 per cent, higher than the best rolled steel, and it has. besides, the additional quality of inconrodibility. The mechanical possibilities open to such an alloy are endless. For example, the small Cast propellers used in hydroplanes or high-speed motor boats are subjected to enormous strain. Some propellers used in. such boats make 150 Q to 2000 revolutions a minute. The . strain on a blade 16in long, with a pitch of 40deg, and with the edge of the blade thinned down to an eighth of an inch, is so great that an extraordinary metal is required for this use. Manganese bronze bends at the blade tip and becomes useless, but monel metal has been fully tested in such service, and proves tc be absolutely rigid. Butter and Microbes.— A few years ago attempts were made to use for illumination long tubes filled with vapour of mercury and lighted by electricity. Lamps of this sort have been tried in various places. But while the light is both soft and brilliant, its colour—for itlacks red rays—has limited its use. In France recently two scientists have made a curious set of experiments to put this light to other practical uses. The lamp is rich in what, are called ultra-violet, rays- - rays which do not. appear as light to the eye. but which affect a photoghaphic plate. These rays, the two scientists knew, produced ozone, hence they should have microbe-killing power. In the course of their experiment* thev tried them on butter. The reason- that butter becomes rancid "is because- there/.are in it certain be sterilised, for the harmful microbes are present in the water used for washing the butter, and the water is in quantity five to eix times that of tb?' milk. So far no inethod simple and practical has been found to ebarilise the water needed, until Vo eminent scientists, Messrs Dome and

! Da ire, tried subjecting ji to the ultra: i walc> !*.■#* of the mercury vapour lamp—asiu jshold! the microbe colonies were reduced from 200 and even 500 to a bare 20. Ordinary butter became rancid in a week; butter worked with this sterilised water could not be told from fresh butter a month after it was made. —Talking Moving Pictures.— One of the latest implications of the kinematograph is the combination of moving pictures with the phonograph, whereby both' action and sound are produced. During the- past few months several devices of this type have been elaborated, all of which are carried out more or less upon the same lines. The phonograph produces the sounds, either of a song or speech, and the effect is so produced that the movements of the mouths of the characters ; on the screen synchronise with the utterj ance of the phonograph, so that the figures in the photographs appear actually to talk j and sing as they move and act. The general moans of ensuring synchrony between the two machines is by misia-ns of dials. On the front of the iphonograph is a small dial with an illuminated hand which revolves as the record is played. On. orw corner of the film is another small dial, the hand of which Likewise rotates, and the operator at the projector has to see that the movement of the hand on the picture dial coresponds with that on the phonograph. The result is not quite perfect, as it entails no little skill on the part of the operator to keep the speed of the projector handle the same as that of the phonograph, otherwise lagging or advance on the part of the picture projection ensues. The best j arrangement of this kind that has yet been evolved is that of a French inventor. j In this instance the phonograph, though placed beside the screen and therefore some distance from the operator, is nevertheless controlled by him, as the phonograph is electrically driven, and the arrangement is "so devised that the picture and phonograph must maintain absolute simultaneous ■movement, since thisy are operated to- , gether.