SCIENCE NOTES.

Otago Daily Times, Issue 13586, 7 May 1906, Page 10

SCIENCE NOTES.

~ Tho results of a study of phosphore«« ceuco in animals by Professor M'lntosh, published in th© Zoologist, seem to havo an important bearing on tho problem of the light, of tho future. Tho most striking thing about animal phosphorescence 's the simplicity and economy of tho mechanism by which it is produced. There is no waste of energy in tho form of heat or other useless emanations, all is converted into lioht. On tho other hand, :n the very b«t artrficial light only a small percentage of the energy expended in producing it appears as light. A careful study of animal phosphorescence, then, mav possibly lead to great improvements in our present methods of lighting. Somo interesting investigations as to tho cheapest form of light carried' out at the Allegheny Observatory indicate that man must learn of tlio fire-fly and glowworm. This conclusion was the result of a careful spectroscopic study of the firo-fly's lamp, anu a comparison of the same with sunlight. It was found that, all tho rays omitted aro light- rays, and that no energy is wasted as heat or other invisible radiations. Sir Oliver Lodge has indicated how tho phosphorescent lamp of tho fire-fly may bo imitated. Certain phosphorescent powders are to be introduced into a. Orookes vacuum tube, and this is to bo made to glow by passing an electric current- tnrcuub it.—Londop Glohc- — A writer in the Revuo Scientifique, speaking of the inroads of the sea upon the borders of England, fays that letween Kibblo and Dee, on the cast coast., tho land has been submerged since the fourteenth century, and the work is still going on. The walls of a castle that only 50 years ago stocd half a mile from tho sea aro now washed by the waves Near Land's End a whole region of 227 square miles has disappeared with more than 100 towns and villages. Since the time of Edward I the area of tho Duchy of Cornwall has been greatly reduced, and plainly "so since 1776.. At Selsea, Sussex, ships now cast anchor along a line that is called "the park," and which was formerly a park for deer. At Bexhill-on-Sca a submerged fuTest is visible at low tide. In Suffolk and Yorkshire many; towns have been overwhelmed in comparatively recent times. Four hundred houses wero carried away in a single year- at Dunwicli. Bet-ween 1535 and 1600 four churches disappeared. In 1399 Henry TV disembarked at the port of Ravensburgh, but sii-co 1538 Ravensburgh is no more. Baston, once an important town, could count, a century ago, only a dozen inhabitants and two houses. Tho 53 years from 1867 to 1900 wore marked by a reduction of *h« area of Great Britain from 56,964,260 to 56,782,053 acre 6. In a- third of a century tho loss has been 182,207 acres. — To test tho presence of coal-tar dyes in sueh things as jam, fruit svrups, or any other very red article of food, all that is neeossary is to boil a piece of white woollen cloth, first wet thoroughly with boiling water, in tho suspected article for five ot ten minutes, and then wash ont the cloth in boiling water. The natural colouring d tho fruit will leave tho cloth only a dull pink in hue. while artificial dyes make it t brilliant, red. Honey is often adulterated with glucose, and its presence can be discovered bv putting some of tho honey in spirit of wine. If glucose is present, it. will cause turbidity in the spirit, and will settle at the bottom in a thick gummy mass, while genuino honey forma into a floceulent precipitate, and when it has settled, leaves no turbidity. Adulterant# are not. always added because they are chcapcr than tho genuine article, but the public have a right to know when they are used; and it would be a distinct gain if, in case of suspicion, a, simple test could always be apolied. Ihere are people to whom gentle and systematic exercise means a new enjoyment of hraltli and longer life; others take up athletics in so violent a fashion as to lead to over-development, in so far as too much time and energy are given to certain systems of exercise, and tho balance of Nature is destroyed. The hapDy medium seems to be struck in a book which comes from the Anglo-Danish Publishing Company, 188 Strand, London. It is entitled My System," by -T. T. Mullor, who has been successively a lieutenant in the Royal Engineers, a private engineer, and an inspector of a sanatorium for consumptives. Ho now proposes to snend his time >n developing "My System," in which, in tlw hook and accompanying chart, 18 forms of simple exercises are laid down and explained. He promises health for 15 minutes * day spent in hie exercises. The writor was at ono timo a delicate boy. but by a series of gymnastics and physical exercises developed himself into perfect physical con-, dition. Tho value of fresh air and cold .water is duly set down, although in our climate it is a counsel of perfection to recommend that every day you should let the "sun shine unon you," and also that vou should not allow one day to pass without every musclo and organ of the bodv being set in motion. Stagnation, says Muller, leads to drooping and untimely death.Motion is life. He directs special attention to keeping the skin .in health, and to cxercising tho middle of tho trunk of the lrody, which is most neglected. Skin gym* HB6tics and exercises of the muscles of' tie waist are what nine people out of every ten, ho tells us, stand most in need of.

— It is quite possible that the device of the radium clook may bo so perfected from a commercial point of view that we mlv have on the market a, "clock" which will go for at all events 20,000 years. Mr Martinoale, tho well-known manufacturing chemist of London, is the inventor of this phenomenon in clocks, and a writer in the Scientific American describes tho device in detail "Thoinstrument is very 6ma.11, being' inclosed in a mahogany framo measuring about 6in by 4in. There is a email glass tube in which is placed about one-twelfth of a grain of radium, and supported in an exhausted glass vessel oy a rod of auartr« At tho lower end of this tube is an electroscope, consisting of two aluminium leaves' or films. The surface of tbe glass vessel is treated with phosphorio acid, to render it* conductive. At intervals of one minute the silver leaves undor the action of tho radium move apart and touch tho sides of the gla6s vefsel. This action is caused as follows : After the Beta rays arc carried away, tho positive charge which is left behind is passed on to thoso two leaves. Under tHa stimulus they expand until one of them

touches the side of the glass vessel. This contact causcs the charge to bo convoyed to the earth. Tho leaf then falls back t<«

its original position, by gravitation, when the ovele of operations is once more repeated, and continued until the, circuit is broken." Tho' exact and continuous regularity of the movements turns the instate ment into a clock, the life of which 16 estimated at some scoro of thousands of years, so that, although tho problem of pernetua! motion has not been solved by Mr Martindale's remarkable invention, it is notexactly hyperbole to speak of a clock for eternity. — Tho straightest thing in Nature or art is a ray of light when passing through a medium of uniform density. Henoo the eye is enabled to test the straightnees of an edge or tube by holding it as nearly aa possible coincident with a ray of light, such parts as depart from straightness then intercepting a ray and causing a shade ta bo cast upon other Darts. It is not known' at what, early period in tlio history of mankind tho discovery was roado thati strnigbtness could be thns determined. Iti is certain that thousands of mechanics use the method daily without being able to