SCIENCE NOTES.

Otago Witness, Issue 3031, 17 April 1912, Page 76

SCIENCE NOTES.

—Tho Utilisation of Grape Pips.—

The utilisation of by-products is one of the most striking characteristics of modern industry. A recent example is found in Italy, whero a means has been discovered to turn to account the hitherto worthless pips of the grapes used in wine-making. Oil is now extracted from them on a commercial scale by a process of direct healting with tetrachchloride of carbon. The latter is obtained in abundance in Italy in the preparation of electrolytic soda.— Scientific American. —Electric Railroads in the Pyrenees.— About 300 miles of railroads are being built in the Pyrenees. These railroads are to be operated by electricity which will be furnished from water-power stations in the mountains. Power will be supplied at a voltage of 55,000 volts, which will be stepped down to 12,000 volts for the trolley wires. The locomotives will be provided with transformers for further reduction to 235 volts. —Mining in Formosa. — The coal and sulphur mines of Formosa in 1910, according to a consular report, showed decreased production, and consequently smaller exports. The decrease for coal was about one-half, and sulphur probably a little less than half. Lack of good equipment is a cause for the unprofitableness of coal-mining, but the equipment would, no doubt, be improved were the quality of coal to be mined better. Goldmining in Formosa has not prospered like many other undertakings. Instead of the production growing, it has decreased during tho last two years, but a larger output for 1911 is predicted. The total production of 1910 was £190,000, a loss"of £50,000. , —Wonderful Telephone Centre.— The now Avenue Exchange in the city of London, when complete will (says the Standard) be in many respects the most up-to-date telephone call office in the world. The cost has been estimated at £160,000, and 10,000 subscribers can be dealt with. To tho uninitiated the " call" stands at the new office are most intricato, especially when it is considered that in the busiest part of the day 5000 conversations may be concentrated on them, with a little ar.iny of M 0 girls switching "on" and "off" during! 16 hours of the 24. The "Avenue," again, is established to reduce waiting to a minimum. Every call will light three tiny electric lamps. These are arranged in the sections manipulated by nine operators. So that, directly the call is made, three signals will gi. up at the Avenue, and nine attendants will see them. Recently tests were made on over 15,000 wires carried into the office, and an army of gii J Is and officials were noting results. —Spidsrs' Threads in Astronomy.— The cultivation for scier tific uses of certain species of spiders, solely for the fine threads they weave, has an important bearing upon astronomy. No substitute for the spiders' thread (says the Scientific American) has yet been found for bisecting the screw of the imicronometer used for determining the positions and motions of the stars. Not only because of the remarkable fineness of the threads are they valuable, but because of their durable qualities. The threads of certain spiders raised for astronomical purposes withstand changes in temperature, so that often in measuring sun spots they are uninjured when the heat is so great that the lenses of the micronometer eye-pieces are cracked. These spider lines are only one-fifth to one-seventh of a thousandth of an inch in diameter, compared with which the threads of the silkworm are large and clumsy.

—Why Certain Colours Clash. — When the eye has gazed fiddly at a colour it becomes momentarily, blind to ?hat colour. The greater the impression Se colour has .made the longer u> the eve blind to it. Every woman knows how dimonlt it is to pick out a certain tint when she ha* before her successively pieces of material of many tints of one co our The eye seems to become saturated with a colour until the retina's (the retina is the screen at he back of the eyeball,.to. which vision is duel ability to perceive vt is temporarily spoUed. In 'this "condition the eye seems sensible only to one colour and that the complementary (any two colours which together produce white lights are complomentarv colours) of the other. Thus. 18 explained the familiar phenomenon that wnen the eve which has been fixed upou a bright colour turns away a patch ot its complementary colour instantly appears before it.—Popular Science &iftmgs. —Novel Fan for Dining Tables. - It is always difficult to break away from old ideas. The disc type of electric fan has shown no marked change in design since the dav it was first introduced. It still throws a stream of air in a single direction. and in order to distribute the cooling effect of the fan to better advantage, various schemes have been devised, such as turning the fan bodily or shifting direction vanes before it. An entirely new scheme has now been evolved, in which the fan is'radicallv altered. This fan throws a centrifugal" zone of air. It is mounted on a vertical shaft and its blades are also vertical, giving it a cylindrical form. As this revolves it sucks in air from ttlii .top and bottom and throws it out centrifugally. A fan such as this placed at the centro of a dining table serves to cool all the diners uniformly. --Measuring Stars' Brightness.— Stellar photometry, or the measurement of the brightness of stars, has had great development in recent years, and is yielding quite a new conception of the universe. The apparent sizes, due to brightness, are' now measured with considerable precision (according to Popular Scier.ce Sittings). The differences aro much greater than they appear to tho eye, and the standard adopted for the first magnitude is 100 times the brightness of the sixth magnitude, or thei faintest star visible to the naked eye, each magnitudo being 2.512 times as bright as the next magnitude below it. The system of defining magnitudes ha* brought confusion, as the brighter stars are now larger than first magnitude. Zero and minus magnitudes aro thus given to the most brilliant stars, and, measurements being carried out tc decimals, Sirius, brightest of all, is assigned to magnitude 1.58. One estimate of the number of naked-eye stare is 7205. The number of tho tenth magnitude is calculated at 720,000, and it is believed that i*-lie total down to tho seventeenth magnitude is 100,000,000 at leasb. Newcomb found tho total light of all stars to be about oneeightieth of that of tho full moon. Ohe

of the strangest of discoveries is that the illumination of the invisible stars is much more important to us than that of the visible ones, and_ blotting out the latter would lessen the light of the moonless midnight sky only one-twentieth.