Progress in Science.

New Zealand Graphic, Volume XLV, Issue 21, 23 November 1910, Page 48

Progress in Science.

The Advance of Aeronautics.

A Huge Propeller-Testing Plant.

ITH a. view to placing them- ■■ I selves in a thoroughly sound. 11l position for coping with future airship orders, Messrs. Vickers Sons ana Maxtin, the iamou- naval constructors of Barrow-in-Furness, have just installed near their works a huge whirling table. This firm has the construction of a rigid dirigible for the British Navy at present in hand. Beyond the fact that this huge vessel will be somewhat after the Zeppelin type little is known about- it. It is certainly going to he a big one, and it is thought that -MX) horse-power at least will be used for driving it. PropelIrse on a vessel of this sire and power run to very big dimensions. And inaasmueh as designers work very much in the dark when planning big aerial propellers, Messrs. Vickers Son and Maxim. with characteristic thoroughness, have decided to collect reliable data bearing ut on propeller design. It is obvious that the only correct method for testing propellers is to measure their thrust while they are moving forward in the air. To enable this to

be done, th- Vickers firm has buiit a steel tower from which is suspended a big cantilever. The arm on which the propeller is mounted i~ 110 feet in length, and is balanced by an arm s<»ft. b ng. carrying a water ballast tank at its onter end. For the- motive power there is an engine of 100 horse-power situated in a cabin built round the tower on the revolving arms. The propeller Ls mounted on a sliding shaft which work- against a spring thrust abutment. To reproduce actual workingionditi ns more thoroughly a car is rigged up. and resistance planes can be put upon the arm to vary the speed at which the arm rotate- Tire motion of the arm is due entirely to the propeller thrust, and this thrust can b» measured accurately to within one per cent. <B> -k •» Dangerous Earthquakes. It has been pointed out that Japan is an ileal country for hydro-electric development be.-ause of its many rapid-ly-flowing rivers. However, there are d ill ’a! ies in the way <<f such development, not the least of which is the danger of earthquakes. Recently, it was proposed to build a large dam to furnish power for a generating plant of huge proportions, but fearing lest there might be a break in the dam Mused by one of the earthquakes so frequently experienced in that region, it was decided to abandon the project.

Around the World in 37 Days. The improvements which have been made in the Siberian railroad have made it possible to accelerate the train service, and reduce the time between Moscow and Vladivostok by twenty-four hours. It is now possible to leave London on Monday and reach Yokohama, Japan, on the second Monday following. By taking the fast CanadiauPaeific steamship, which leaves Yokohama on Tuesdays, the tourist, if he so wished, could reach Vancouver in 26 days after leaving London; and in 37 days after setting out on his worldencireling trip he would be again in London. This, be it noted, is less than one-half the tune taken by Jules Verne’s traveller in his trip around the world. ® ® Colours of Foods. Of the strong addiction many consumers have for the use of foodstuffs that are secretly and highly coloured for the market. the "London Lancet-' 1 savs:— “For some not quite clear reason there

are many people who look upon the brown egg as necessarily a new-laid one, and hence a fair demand for brown eggs has arisen, which is easily met. not by the honest brown egg. but by the white egg, which has been steeped in a dye which renders it visually indistinguishable from the real article. Again, when milk happens to be of a buff tinge, it is commonly held to be richer than white milk. Of course, nothing can be easier than to satisfy this preference for a milk of a creamy shade. White-looking butter is disliked, as looking too much like dripping. The remedy is simple; it is artificially coloured. Vegetables must be bright green to make them look fresh, the consumers of them being quite willing to ignore the fa t that copper does not make them fresh or wholesome. Oh the other hand, curiously enough, bread must be white. “It is. of course, perfectly natural to take colour as a criterion of the dietetic value or flavour of food, and • the attractive or unattractive appearance of food may make all the difference as to whether that foul is. or is not. assimilated properly. The deceit which is practiced by artificially colouring food may thus s-rve a useful purpose, so long as the colouring matter is harmless, but as a rule the proceeding is an immoral one. It does sot follow that because food is unattractive its value as a food is nil, while every form of sophistication is open to commercial abuse. A correspondent recently submitted to Us a brown-shelled

egg which, on opening, displayed a gorgeous red colouring scattered chiefly through the white. On analysis the colouring proved to be an anilin dye. The dye had deposited a niee brown on the shell, but an excess had permeated its pores, and. meeting with the slightly acid contents, was changed to a port-wine eolour inside. Until the egg was opened, therefore, it appeared perfectly attractive, but on opening it the zest to eat it quickly disappeared.” ♦ ♦ ♦ What They Eat and DrlnA in France. The adulteration of food in France is said to result in a profit of £20.000,000 per year. Bread, which may be called the national food of France, has long been adulterated largely with tale, a substance which is not only indigestible, but is exceedingly irritating to the gastro-in-testinal mucous membrane because of the sharp crystal fragments which it contains. Flour is often mixed with alum or with potassium carbonate to increase the amount of water absorbed, with zine sulphate to keep the bread fresh, with copper sulphate and ammonium carbonate, to diminish the quantity of yeast required and to improve the appearance of -bread made with spoiled Hour. Denatured alcohol, costing one-eighth the price of pure alcohol, is used for the manufacture of the liqueurs and aperitifs, which are so largely consumed in France. Alcohol, denatured by the addition of methyl alcohol, is mixed with an equal volume of water and exposed for a few days to the sun, air and rain, which have the effect of precipitating the methyl alcohol so completely that its flavour remains barely perceptible. The mixture is then brought to t*»e. desired

aleoholie strength by the addition of strong spirits, flavoured to suit the taste of the consumer and sharpened by the addition of a pint of nitric acid to each barrel. <t> Electric Light and tie Eyes. Considerable attention has teen directed of late to the injurious effect of certain rays of electric lamps upon the eye. A very interesting communication upon this subject was recently presented by Dr. Stockhausen before the Illuminating Engineering Society of Lon lon, and he pointed out that at excess of rid ant energy, no milter what its wave length, i< injurious. Hitherto it has been supposed that the r«-d and infra-red rays, on account of their heat value, are very injurious to the retina, but Dr. Stockhausen does not believe that under ordinary conditions the effect of these rays is very disastrous. Certainly, in sunlight, these rays may be found in large quantity. The best rays for the human eye are the yellow-green rays. The rays from blue to deep violet do not appear to produce serious effects, and even the rays in the ultra violet section of the spectrum do not do very much damage. The rea.’ly injurious rays appear to be those which belong in the extreme ultra violet section. These rays, are not found in ordinary sunlight, but appear in the light produced by quartz-inclosed mercury vapour lamp®. As ordinary glass is opaque to these rays, it is a simple matter to avoid them.

Ike Me*aia< of 'Gold-fined.” What does “ gold filled ” mean? Pro*, ably most people who buy gold-filled watches fancy that they are impregnated with gold. As a matter <S fact the term is misleading. Gold filling consists in taking two sheets of gold, be. tween which is placed a section of aoMerc< ated base metib This metalHj sandwich is heated and pressed, so that thd three parts are welded together, with the gold outside. ♦ ♦ Milk Powder. The American process of reducing milk to a powder has now been introduced into Norway. One of the new companies formed has contracted to deliver 300 tons of dry milk each year for three years to an English firm. The dry milk is used largely for invalids and convalescents, oa ships on long voyages, because of its keeping qualities under all climatic conditions and its convenience of transportation. <®> <s> <s> Aneient Cheese. Newspapers report that in the Alpine regions of the Swiss cantons of Vaud and Valais cheesemakers will keep their products for years. They assert thafi cheese improves with age. At Lea Or* moots, in the canton of Vaud, it is customary to make special cheeses for certain family feasts. They are tagged with explanatory labels and eaten several years later, at other feasts, or even at funerals. Often such cheeses are bequeathed from one gt neration to anctb.es as family souvenirs. Recently, at Les Ormonts, in a concealed shelter, there was discovered a cheese dating from 178.5. It was as hard a> a rock, and had to be cut with a saw. It is reported to have tasted good.