SCIENCE NOTES.

Otago Witness, Issue 2677, 5 July 1905, Page 68

SCIENCE NOTES.

— The -waters of Bath, Buxton. ConIrexeville, and other places exhibit a comparatively ieeble degree of mineralisation, and yet (says the Lancet) theie can be Ho doubt of their therapeutic value. So * far.-- the findings of the physicist and the --chemist do not afford a satisfactory hypo-^ - thesis in regard to the therapeutic- value bf 6uoh waters, question now arises whether the ,-facfc that these waters are Tradio-aotive will supply any explanation. Most, if, not all, of the thermal springs Sn Europe which have been examined have Ibeeri found to contain, in slightly varying ' quantities, argon and 1 helium, and m the majority of "oases these waters have been ■ffound to be distinctly radio-active, tie -seem here to be" getting some light at length on wlfat has long beoji an enigma— (that- of *wo waters showing the same fchemica! composition as regards their saline (constituents,— the one of natural origin is distinctly superior, thcrapeutically epeafcW to the r one artificially compounded^ The fact is that a natural water weHmg iup from the earth is at the moment of fits discharge from its source radio-active, while ordinary drinking water, rain water, srell water, river water, and the like do »ofc generally exhibit this property to any extent. Further, since the property of x-adio-activity is rapidly evanescent, the emanation quickly vanishing, it follows that it *he benefit derived from undergoing a course of waters is due to tbe radioactivity cf these waters, Hie treaimentshould obviously take place nea,r the source or the- water. . . —No pre-eminent man of science nas 'ever been subjected, in his latter years, to a more critical and exacting test than that -which the recent development in physics has brought to bear upon Lord Kelvins toast work. There have "been parallel mItances, but none more crucial. The name ol Cuvier at once suggests itself, and, ni $&* measure, tbe name of Owen. These were distinguished biologists— the Irencnaaan being almost. fit to >rank ; in his own department, beside Lord, Kelvm— to whom, -&ri •, their later years, there was presented -the \ided of onanio evolution; to Cuvier <who died in 1852), in a merely inchoate form; to Owen, in the fight of Darwms snas'jerpiece. But, the test was too much for tiem; they died with their faces eet fesainsfc the- light. Similarly, radio-activity, jftnd all it implies, has* initiated in physicg kn epocli which, is not only new. but the T«y porsibility of which was denied by irany of Lord Kelvin's leading contemrJoraries, two, three, four, or five decades *go 7 Their great survivor, however, has toot onlj stood the test, but has actually made as important contributions to the. new departure as ho did to ihe last great (departure in' physios which signalised the fifties. Lord Kelvin reached! his eightysecond year on the 26th of June. — C. W. S., an tiie Pall Mall Gazette. ■ — A new ocean-going steamship is being built at Stettin, Germany, in which will he embodied the invention of a Hamburg •ngineer to nrevent the vessel from rolling In a heavy sea. The device consists of a massive balance wheel, mounted so as to oounterect the shifting of the ship's centre of gravity. It is said to have worked Satisfactorily in models constructed to test Jt. Theoretically, ifc should be equality Successful in a large vessel, provided that the same relative proportions of hull and balance wheel are maintained. At present >he rolling of a. big steam vessel is parti- ■ 'ally counteracted by bilge keels built into ihe sides of the hull. The resistance which these keels offer to the water, as the .craft rolls, acts as a brake antt steadies )ier by shortening the oscillation. Without bilge keels, for example, a top-heavy battleship would be in serious danger of rolling too far and capsizing in a heavy seatray. Every ship has an angle of safety which cannot be passed without shifting the centre of gravity &o as to make it impossible for her to recover herself. The object of the Hamburg engineer's balance jr^iwaol cUuuce is not, however, to ensure to '

the vessel a greater degree of safety, but to maintain her stability and reduce the causes of seasickness p-nong the passengers which the steamship to be equipped with it is expected to carry. " The great ocean steamships are built so long now that pitching in the heaviest storms is. practically impossible. Thus, rolling, which reaches its maximum when the wind and sea are abeam, is the most seriou3 motion these vessels have to contend against. But any device used to steady a steamship in such a. position and counteract the roll, which naturally relieves her of the pressure of wind and water, produces a corresponding strain upon the hull. Whether any device can be employed that will stop rolling altogether and not strain the hull to the danger point is an open question. Ocean travellers will doubtless welcome the introduction of a device which will absolutely preserve the equilibrium of the vessel in which they are sailing, and secure them against seasickness; but they must be assured that ite employment does not put the safety of the craft in jeopardy. It is better to suffer seasickness than shipwreck. — San Francisco Examiner.

— There is undoubtedly a practical art of discovering springs. Indians or frontiersmen can find water in the desert when a "tenderfoot" cannot. Mexicans and experienced prospectors can similarly find ore. These arts consist mainly in the recognition of superficial signs which escape the ordinary observer. It is not necessary that the operator should consciously note these signs separately and reason upon them. No doubt he frequently does so, though he may not give away the secret of his method to others. But in many instances he recognises, by association and memory, the presence of a. group of indications, great or small, which he has repeatedly found to attend springs or oi'e deposits. This skill, due to habit., is often almost unerring for a limited district, but under new conditions it breaks down. Old miners from California or Australia have often made in other regions the most foolish and hopeless attempts to find gold, because they tksnglit this or that ulace "looked just like" soni9 other place in which they had mined successftuly. Apart from the magnetic minerals there is no proof that ore deposits exhibit their presence and nature by any attraction or other active force. With regard to water, however, there maybe an action affecting the temperature and moislure of the, overlying surface. Even here, how<-\er, it 6eems more likely that such effects are manifested visibly to a close observer rather than by direct affection of his nervous or muscular systems. The favourite fields for water diviners are regions in which water is. abundant, bufc not gathered upon given horizons of impermeable strata upderlying porous rocks. — Cassier's Magazine.

— The development of the internal combustion engine for marine purposes is being watched with great interest. As Sir William White pointed out recently, the adoption of the now familiar motor boat means that the same ranges of power and action as are obtained from the best modern reciprocating engines and boilers can be secured at one-sixth of the weight with the new motor. This statement he made on the authority of Sir John Thornycroft. who has devoted much thought to this coming revolution in the propulsion of small craft. Th-3 British Admiralty are so convinced of the -wisdom of adopting the internal combustion engine at sea that they have carried o\it a series of experiments. The first result has been the decision to build a motor launch for the King's yacht, and there is also some talk of this type of engine being utilised in the new torpedo boats which are about to be built. Ifc is realised that not only does the internal combustion engine give equivalent power to the reciprocating engine and boiler with a great economy of weight, but that the new engine will lead' to a further economy, owing 1 to the reduction in the engine room and boiler room staff which it will be possible, to make. The motor boat has become one of the toys of the wealthy, and yacht builders report that many lovers of the sea vrho have hitherto

spent a large part of the year in yachting are now ordering motor boats, which will cither supersede their sailing craft or will be used in connection with them. — Cassier's Magazine.