SCIENCE NOTES.

Nelson Evening Mail, Volume XLVI, Issue XLVI, 25 January 1911, Page 7

SCIENCE NOTES.

MAKING SAWDUST SOLID

A machine ha s been inverted that turns sawdust.. shavings, and chips i-iio solid wood. The material is carried on a rotary belt to the machine's hopper, thence to ap lunger chine's hopper, Through, the centre ri the mould into which, the shavings and sawdust are forced is a small hempen rope. A pressure of 20 tons per souare inch is exerted, and the solid brdy is driven out of the machine in a shape similar to a round slick of wood of 4i n diameter. The machine is said to turn but about six tons of sticks a day.

A LESSON FROM NATURE

Science owe s nany a debt, especially on the practical side, to the instinct of the lower animals. One of these obligations may be cited ir the matter of the construction of dams. Engineers have frequently built dams straight across streams, the object being, in some cases, to save expense by sparing material. But beaver arches' his „ darn against the current, and experience Las shown that this form of dam is best for resisting floods and the impact of floating i<j c . Acting upon the knowledge which' is instinctive will; ..the beaver,- and which human calculation approves, the great Bear Valley dam in California and some ether dams' constructed -"sprain recent years have been made su that their stability depends largely upon the resistance which their arch'-'? form presents. AN ANCIENT SCIENTIST. "Physical Science in the Time nl Nero" is the title of a recently '.:

sued book, which is -a trahslatio;. • » the "Quaestiones Naturales" ' •■■'

Seneca. Considering the state of physical science in that antique S'neca was an observer of no men, aoiiity. He observed the magnifying pewer of a spherical water lens, recognised tlve three kinds of moven.ent associated with -earthquakes, dimly perceived the doctrine of the conservation of matter, wrote on the effect of forest denudation, on the quantity of rainfall, on the character of floods, etc. To be sure, he did maintain that the earth w T a s fixed and located within a revolving starry dome. That does not seriously mar the value of observations made at a time when observation itself was i'row'ned. upon in favour of sheer philosophical speculation. TO LIGHTEN METALS.

Many unsuccessful experiments (states '"Meal Industry".) have been made in the hope of utilising ma_gnesium, as, owing to its extreme lightness it would be most suitaoxe if it could be alloyed with another metal so as to produce an alloy wh'ic-h combines strength, with lightness, as there is a considerable field for one not only in the construction ox aeroplanes, but for many other branches of engineering where weight is a consideration. Magnesium has a specific gravity of 1.7, so that it is much lighter «ven than aluminium, whose specific gravity i s 2.6, wbile that of iron is- 7.8, so that magnesium is more than five times as lijjht as iron and 50 per "cent lighter than aluminium. A recent French patent, describes, a process of manufacturing alloys of magnesium and zinc, containing as much as,from 90 to 96 per cent magnesium. The same inventor claims to have succeeded in making a practicable alloy of calcium, whose specific, gravity is 1.58, and which is therefore £yen lighter than magnesium, with zinc, copper, or aluminium, or a mixture of these three metals. WEIRD GERMAN INVENTION.

Two 'Germans—,the electrical engineer, Christopher Wirth, and/the manufacturer, ~. Christopher oße£k, Lav© invented a ship whose engine can be started or stopped, and whose helm can be controlled .by the elec-ts-cal wave s communicated without wires to a receiving apparatus on board the mysterious vessel by a sending apparatus on shore similar to that required for wireless .telegraphy. By of _ th'esfe -electrical waves a gun on board the ship Jean. be .fired, and signals can 'be transmitted both by flashlight and by bells. All these wonders are possible within a radius of 18 miles from 'the wireless station on shore, which transmits the controlling force to 'the vessel. The practicability oi the new invention has been demonbefore numerdus experts by .exhaustive experiments on the Diit-zendleich,-a large expanse of water ; iiear Nuremberg", with a motor boat, the Prinz Ludwig, Messrs "Vfarth and Beck state that their system'can be with equal facility to air ships and submarine vessels. With its hol.p- it would be possible, without risking human lives, to block the entrance to a harbour, direct an unman red submarine to the midst of a hetile fleet, and steer an unmanned airship over hostile positions.

FIRST BRITISH RADIUM.

The first radium that has been extracted in 'Great Britain, from (British ore was recently exhibited ir. London at the factory of the British Radium Corporation at Limehouse. The occasion was marked by a gathering at the factory. Up tc row SSO 1 milligrammes of oure radium have been produced^'and the process adopted by Sir William Rainsay and his chief assistant, Mr Norman Whitehbuse. is so rapid that radium which has been extracted in two months at Limehouse cculd not be extracted in less than a year by the latest'method in use oh the Continent. The gentlemen who visited the works were shown a quantity -of 10 per cent radium, which at - the present price of about £2,0. a milligramme is worth about £II,OOO. It is stored in a specially-constructed safe, lined with lead and asbestos, and remarkable ,precaution s are taken to ensure its"safety. Pitchblende, the mineral from which ra-

J;iim i s obtained, is very rare, and j o:ily two deposits of serious magni- ' tr.de have so far bc-en located., in Cornwall and in Austria. fclxplain- '... „• the method of work and its recults. Sir William Ramsay said that j n:<} pitchblende ore was obtained f.om the Trenwith mines, near St. I\es. Cornwall, and delivered in a ; concentrated form at Limehouse. 'J i the uranium and iron are dissolved, and the next stage i s to precipitate the radium out of the clear liquid. When precipitated the radium H converted into radii-.u bromide, r.r.d by repeated crystallisation this Lromide wa s separated from its various grades of commercial saleabilif.. •'•'The actual time taken in gett'na the radium liquors is a week.'' sa'd Sir William, "and the crystallisation which goes on afterwards tKkos a couple of months, 'five latc= t Continental process occupies a year.'-' As illustrating the certainty of rhe process in use at Limehouse, he mentioned that of 530 milligrammes .produced, only que milligramme was feft behind in the liquid. Up to iow just over balf a gramm e had been extracted at Limehouse, but the is now going on continuously, and th-e works are laid out to r.roduce one gramme a month. 'So tar only (five or six grammes are known "to have been produced in the whole world. "It has been supposed,'' said Sir 'William, Austrian pitchblende is particularly rich in radium, but it is no richer than any other. Moreover, the supply of Vrtcli-blende in Cornwall, as far as I can judge, is very much larger than ii> Aristrla. There is no other source <jf supply of such magnitude known •At. present. The supply of radium in l.'vcut Britain is assured." Ques-.f t.ontd as to the practical uses of rar'ium.Sir William Ramsay said: "It has been, used to cure rodent ulcer, v hich is somewhat allied to cancer. 'I hen ther are gases given off called •rsidium ,- manations, which dissolve i-i water, and these have been found c:;tremely effective in ease s of rheumatism, gput, and neuritis." Sir Wil- •'"- -3771 added that the energy of radium "minished so slowly that one-half -•'lv v.-or.ld have spent itself in 1700 years.