SCIENCE NOTES.

Otago Witness, Issue 3084, 23 April 1913, Page 68

SCIENCE NOTES.

—How Old is Man.— Professor G. Frederick Wright estimates that life has probably existed on the earth for 24,000,000 years, but that it cannot possibly have begun as long ago as 50,000,000 years. Man’s antiquity cannot, he says, bo less than 10,000 years, while it need not bo more than 15,000. The evidence that man appeared in Tertiary time is regarded by our authority as very doubtful, and the Post-Tertiary ago has been a relatively short period, while the known facts of human development can be amply accounted for by 8000 years of time before the historic record began. —Food to Keep Plants Warm. — It "is well known, of course, that human beings and the lower animals are better able to resist cold when they are well fed; but it is interesting to learn that a German investigator has announced that feeding plants has the same effect on them. Ho declares that the introduction of organic substances of nutrient character (carbohydrates, alcohols, acetone) into tho plantcell heightens its resistance to cold, even in the case of tropical plants. Different substances protect in different degrees. The sugars stand highest, then come glycerine, the alcohols, and acetone. Tho removal of tho protective contents restores the original degree of resistance. —Highest Tower in tho World Proposed For Germany.— A great steel tower that will rise to a height of 1600 ft, surpassing the Eiffel Tower by more than 600 ft, is proposed for Uusseldorf, Germany. If the plans are carried out the tower will rise above the River Rhino, a part of tho lower portion of it forming a bridge. The legs of the tower at right angles to the bridge will rest upon two stone piers, which will lie about 650 ft apart on a line with the central pier of the bridge in tho middle of the stream. The arches at the base of the tower will bo 300 ft in height. Tiie top platform, which will bo 160 ft below the extreme summit, is to bo 80ft square. The tower will be used for scientific purposes, and will have a wireless installation in its top. —A Fortunate Accident.— The working of motors at long distances from the source of electric supply was discovered by an accident. Soon after the opening of the Vienna Exposition in 1873. a careless workman picked up the ends of a couple of wires which ho found trailing along the ground. Ho fastened them to the terminals of a dynamo to which he thought they belonged, while they were really attached to another dynamo that was running in another part of tho grounds. The dynamo to which he fastened the wires was not running, but as soon as the wires were placed in its terminals it revolved as if a steam engine was driving it. Thus originated one of the most revolutionary applications of electricity. —Language “Canned” for This Museum. — Professor Ferdinand Brunot, of tho Sorbonne, is establishing a museum of voices with a view to preserving for future generations tho voices and words of to-day. He believes the phonograph as wonderful as Gutenberg’s printing. Beginning with a. small donation from a private individual and £B-0 from the university, ho made a tour, collecting French dialect discs. Now he is making a collection of 800 discs on a tour of the world from Poking by way of America, including even Sioux Indian legends. This collection he means shall embrace every spoken language of the world. He hopes to make it as complete as the National Library. Every dialect representing every national character, statesman. nreachcr, actor, or orator is to be collected in this vast phonographic museum. Tho degree of saltncss of the Irish Sea is the indicator Professor H. Bassett proposes to use for long-distance weather predictions. The salinity is found to vary in a period of alxmt one year, with corresponding changes in temperature, tho water being salter and relatively warmer in winter and spring and fresher and relatively cooler in summer. It is argued that the alterations of temperature must affect the number and character of tho cyclones coming from the ocean. The changes of salinity and their time of occurrence have been found to precede certain seasonal types of weather, and it is believed that monthly observations of tho saltness would give a general weather forecast for tho British Isles four or five months ahead. —An Incendiary Bullet.— Tests have Ik cn made in Germany with a snecial projectile which is intended to rope! dirigibles and which, is designed not only to pierce a gas envelope hut, also to set (ire to the gas. This projectile, fired from the old German rifle known as “model 71.” which has a calibre of 11 millimetres, is provided with little wings that open in flight under the influence of a spring, compress'd while the projectile is still in tho rifle barrel, but expanded as soon as the muzzle is passed. An ordinary bullet leaves such a small hole in an envelope that the gas escapes through it but slowly. The wings on the improved bullet tear a hole of appreciable sk" in the fabric, and retard the bullet sufficiently to cause a friction deviee to ignite fulminate contained in the bulla. —To Steady Monoplanes.— M. Moreau, of Paris, has Ivon testing a monoplane which, according to the Scientific American, is provided with an automatic stabiliser. He claims that ho has flown 35 minutes without touching a lever. s(eevjng with has feet. The writer, who saw a short flight, believes the feat is possible in good weather. The monoplane has pro-vi-dnn both for automatic stability and for personal control. The lateral automatic stabi’itv i= secured r-artly bv the wing shape, partly bv the low placement of the m'-ss centre. The.se are old and obvious dWiccs. which serve in favourable weather

and in easy manoeuvres. Longitudinal automatic stability is secured l by placing the pilot in a pendulum seat shielded from tho wind, movable only in a fore-and-aft direction, and actuating control cords running back to the horizontal rudder. This general pendulum device for automatic control lias formed the basis of many patents, but as now applied seems to have some noteworthy features. —Photographing Diseases.—-

Developments in the use of the kinematograph as an aid to medical science arc becoming more and more extensive. For some years photographs have been in existence showing tho movement, growth, and character of different types of bacilli. Moving picture illustrations are already employed by public health bureaus in tho United States to show the menace of such diseases as smallpox, typhoid, etc., while a French surgeon has used the same medium for the explanation of an operation. A new field for the moving picture is now suggested by Dr T. H. Weiscnburg, of Philadelphia General Hospital, who advocates its employment in tho diagnosis and study of nervous diseases. Dr Woisenburg is very optimistic as to the possibilities of this new adjunct to scientific study, which enables a permanent record of symptoms to be made and sent from place to place and reproduced at will, no matter how rare the case, and he suggests many instances in which kineina illustration would be particularly valuable. —Uses of the Gyroscope.—

In a recent lecture on “New Gyroscopes and Their Applications,” Professor Andrew Gray pointed out that although it is only in comparatively recent times that the principle of the gyroscope —or, as it might more properly bo called, the gyrostat—had been scientifically employed, it had boon well known from time immemorial. In its most familiar form it was seen in a spinning-top. The principle which it represented had been applied in a number of ways in modern times, as, for issuance, in fast-running machinery such as turbines; slow-running turbines for steamships, propellers of aeroplanes and torpedoes. Ho showed a number of tops which revolved by electricity, and explained that they had three axes, which he . called the axis of spin, the horizontal axis, and the vertical axis. One of the tops he placed on a wire, and it travelled along like a tight-rope walker. Another was made to ride a bicycle on the floor of the theatre, the rotating top behaving precisely as a human being does under the same circumstances in order to maintain equilibrium of the machine. A very pretty experiment consisted in placing the rotating body inside a square frame and walking with it first in the direction in which it was spinning and then in the opposite direction. In the first ease the machine wont on spinning quite contentedly, hut in the second it so far resented the action that it turned right over. Many things which are matters of common observation the lecturer explained by the peculiar properties of rotating bodies, as, for example. the superior stability of the paddlewheel vessel as compared with the screw vessel. He also showed how the Brennan mono-rail train acts, and how shins at sea may be steadied by means of a gyroscope. Finally, he showed a working model of a new gyroscopic motor car on two wheels. This is the invention of his son, Dr D. Gray. It seems that, the motor car in question can run on one wheel or two or more wheels with, a single track —that is to say, placed tandem fashion.