SCIENCE NOTES.

Otago Witness, Issue 2509, 16 April 1902, Page 64

SCIENCE NOTES.

— Some interesting experiment- fo\ the artificial production of ram by mean-, of electricity have been carried out m Japan. Tho piobabihty of greater sviccess being uhtainod by this means, in lieu of the system of detonating explosives in the upper air strata, has often been ad\ocated by scientists. This attempt by tho Japanese, however, ib the firat practical effort to pro\e the truth of theory, and it was attended with conspicuous =ueee=s. The trial* were made in the JTuku^uima prefecture. Operation-; were <'ommcuccd at 11 m the evening, but thcie iva,s n<j sign of atmospheric change until 9 o'clock next morning, when a du-ter <,f clouds was obser\ed over the hill on which the experiment wa= held. At length lam began to fall, followed by a second fall at 11 a.m., and afterwards a third, fourth, and fifth — the last being about 9 30 m the e\en ing. The area upon which the lam fell extended over many mile-. — The first gieat engineering feat to be completed in the twentieth centuiy will be the great Nile dam. Tho work is now being pushed rapidly forward, and before very long thousands of sauare miles of hitherto barren and unfruitful land will be transformed inro one of the richest crop bearing areas in the world. The dam, which is built of granite, is a nnle and a quarter aero*-. It is 90ft bjgh above the le\el of the Nile at low wit*?, and on the top is as wide a» Fleet street. In a short tune caraians with their camels will be able to walk across it with perfect ease and safety. Not the least wonderful feature of the woik are the huge sluice gates for holding back the water There are no fewer than 180 of thes-p, and %fet>eeu them they, are capable of booking

back over 1,000,000,000 tons of water. Along with tins immense volume of water there t are billions and billions of tons of a peculiarly rich sediment, which is capable of converting desert into soil so fruitful as to produce three crops in one season. For a distance of 144 miles along the river the influence of the dam will be apparent — in other words, a lake of that «ize will be treated. Hubsidiaiy dams will enable tins \a.-,t expanse of water to bo> thrown into existing canals at a sufficiently high level to migate the country It i» e.-timatcd that the mighty enterprise will cost £5.000,000, but it is also stated that the value of the 2500 square miles of land which will come under cultivation when the dam is com pleted will be £80,000,000.— Ca^ell's Magazine. —Mr Hardmau A Karlr, M.I.C.X . M.1.E.E., icad a paper before tho Manchester fe< tion of the Institute of Eleetiical Engineers on '•The Supply of Electricity in Bulk." Referring to the -chome of tho Yorkshup Powei Company, ho explained that in that four power-station., are scheduled. The three most important arc situated on tlir> coalfields and surrounded with factories and works of all descriptions, and with the exception of a small outlying portion of the area 12 miles i= practically the maximum distance to which it will be necessary to tran^ nut energy. The four station* will a\ crape 25,000-1 hp. each He had made a rough approximation of the U'ps. to which the power will be put — \iz. 15 per cent foi tramway* and light railway-, 60 pei tent, for motors 25 per cent, for lighting to an-, thon-eel iiudei taker* H:wiiiy ion»jdeird the co«t of production and the income to b-> derived. Air Earle said he wa^ of opinion that there wa- a gre it futuie for such power companies. The York-hire Company had a capital slightly over two millions and a-half. and an area of 1800 =quaro mile-, tt. deal with, and prow-ion had been made ni the Parliamentary estimate- for 100.000-i.h.p. That h<ir*e power, he behe\ed. could ho «uc ce-fully dealt with with that capital: but he had no doubt that the '.tation-- would bo loaded long before the demand for power had bt-en -ati-fied in the district, and that ultimately additional capital would have to be rai-od. and the -tation- cnlaiged, and -omo new ones erected. — Some interesting det.u l - bn\e l.iti-lv been published concerning the u-e of o/.oikin purifying uatei Ozone i- oxygen m a highly active condition, and it "emir-, in small quantitie- m the air of the -ca and of the mountain-. Xc.ii licilin an p-tabh-h-ment lias been riec'id foi ihe puipo-e of exr-c-ninenting <>n tl-.e (fleets of ozone- in ridding watei of Jie microbes it contain-. Ozonised air, containing; fio:n two +>■, tiucr» ! grammes per cubn inetie (a tubir metre equals 220.09 gallon-, and a cramme l- about 15 giams Enghfh) i- pa--rd upward into a ! tower which i:> filled with flint-, and iii it? pa-:-age- mecti tlie water (fining down, and thus acts upon it It ha-, Ix c n -liovmi that, a-> regards water from the Sprre. the mmi ber of microbes wn^ decrea-i'l from 6&O.GTQ per cubic centimetre (.061 of a cubic mcL)

to ten, which is practically nil. The total cost is set down at Is 5d per 1000 cubic feet. Ozone has long been known as "Nature's disinfectant," and its application in the purification of water becomes, therefore, a matter of great interest. If the cost can be reduced, this mode of purification may have a chan m of widespread adoption. — The motive power on our grea£ railways forms such an important question that any enterprise made with a new motive power, electricity or otherwise, adapted so as to utilise the existing rolling-stock, not only may at some future time greatly accelerate the present speed, but also introduce great economies, especially if the new power can bo derived from a natural source In Italy tlie railway authorities have been thoroughly alive to this fact; a portion of the railway of northern Italy has been electrically equipped for running by means: of electric motors, as a pioneer installation, and if successful the remainder will be similarly equipped. The Valtellina Electric Railway (says Feiklen's Magazine), which is 62 miles long, runs from Lecco along the shores of Lake Como to Colico, where it clh ides, one branch going to Sondrio and the other to Chivenna. The power of the line is furniphed by falling water from the River Edda, which operates four turbines (2000 h.p each), and which, coupled direct with four Schubert three-phase generators, give a current at 20,000 volts and 15 cycles. This current iled to ten sub-stations (placed about »ix mile? apart) along the route, where it is transformed to 3000 volts, at which voltage tho various sections of the line are fed. The two overhead trolley wires which supply the; motors (the railway track forming the third) ' are hung from steel wires supported on each side by posts spread with crossbeam? ; these also carry the main supply wires (20,000 \olts). The traffic of the line comprise-, both , goods and passenger. For tlie pa^sengci j traffic bogies motor-cars act m place of leco- . motives, and pull four coaches as trailers | (these latter also of the ordinary Italian type). A train of this description l-^ run at 39 miles per hour on all gradients le°s than 10 per cent. : for anything steeper than this " the Cascade " arrangement of motors is used, then the speed is halved — According to Major-general Powell, in the Aeronautical Journal, South Africa, in general is unfavourable to the use of captive balloons, owing to the hills and gusty winds, or "devils" (whirlwinds). He thinks the captive balloon might, on principle, and without imputing blame to those employing it, have been used with better effect in the war. At Magersfontein. for example, when the troops advanced on the Boer trenches at dawn, it would have been more serviceable. The Boer trenches were regarded as immediately at the base of somo rocky kopjes, but in reality were 100 yards in front, and a large numbei of the shells must have fallen behind the trenches. Tho balloon might ha\c corrected this error, but was employed too late. Ascending m tlie balloon is dangerous with rifles accurate up to one mile and a-half, but something must be risked in order to obtain information. To avoid hostile fi'v he recommends shorter ascent c — that is, going up, observing, and then coming down again ; thus preventing the guns getting into action, or, at least, their sure aim. Pompoms and other guns hardly reach the e'^\ation of a balloon at a good height. He nlso believes that free balloons might have been used with favourable winds in order to get information of the Boer positions. — Ordinary folk have little con-option of the tremendous degree of heat represented in the orb of clay, just as they are ignorant, as a rule, that it is hydrogen gas that, blazing in the sun, keeps the universe of life existent. Profe-sor W. E "Wilson ban gnen some interesting detail- respecting the temperature of the sun. He tell« us that the mean temperature is about 6200deg Centigrade Of such a degree of heat, J -uppctc, we can form no adequate conception. Assuming that it is probable that so much of this heat is absorbed by tlie sun's atmosphere, the actual temperature is. set down at 6600deg Of the total heat we receive, of course, only a very small proportion. The rest belongs to s-pace, and is shared by other worlds than ouri. — Dr Andrew Wilson, in tiie Londrn Chronicle. —In IFQ* and 1895 th- d.amcter- o f tho rlanei-- a'icl their thief -atclhte, weie mci smeil h\ lie ob-°r\«»i< of the T^ic k Obscn,-!-toi v, and during the las-t two jeai- thei-c 11 '- -iii I'iiientn have been carefully re\ i-ed by mean, of the great 40in refractor at the Yorkes Observatory. The diameters of Ceres. Pallas, Vesta, and Juno — the four chief member- of the belt of tiny planets between j the orbits of Mars and Jupiter — are found ! to be 477, 304, 239. and 120 miles r. sp Cl . ; tively. Jupiter, whoi-e equatonal and polai di. meter-, aic 90,190. and 84.570 miles. ha = the largest moons: Satellite 111 is 3558 miles in diameter, and .Satellite IV ha- a breadth of 3345 miles. During the more recent ob-ei vation- the clim s of Mercury and Venn- wer eareful'y examined. Though no tiac «'s c. 1 the linear canal system described by other ob-er\er- of Mercury weie noticed, three oi foui large darkish spots similar to the markings on our moon were distinctly \ i-ible at time 1 -. And fainter mai lcing* of the t ;iri 'e description weif» observed on the c'l-t of Venn-.