SCIENCE NOTES.

Otago Witness, Issue 2529, 3 September 1902, Page 64

SCIENCE NOTES.

— The possibility of extracting from sea- [ mrater the gold it contains within its mass lias always formed a fascinating problem, Hot to the chemist on'y, but to the commer(rial speculator as well. Everybody admits that an immense quantity of the precious metal must be held in solution, as it were, Sn tho oceans of the globe, but that it would :pay ma-ukind to be at the expense of securing it is, of course, quite another matter. Still, it is' quite likely that, despite *he scientific difficulties in the way of exitracting oceanic gold, many mouths will water at the statement made by Professor liUpton, of Leeds, who, speaking at the j annual meeting of the Institution of Mining Engineers, declared that, according to Ilia estimate of the amount of gold in the sea, there wns sufficient to give six millions sterling to every man, woman, and Child on the face of the earth. It would be liighly interesting to learn how Professor Jjupton arrives at this conclusion. Certainly the figures are somewhat astounding. — A few examples of the practical application Fcientific education in Germany tere given in the Journal of the Society of 'Artg. The sugar industry is the first illustration of the progress of industry through ecience. In 1840 154.000 tons of beetroot /were crushed, from which 8000 tons of raw Bujar were produced, showing about 5£ .per cent, of raw sugar extracted from the root. Twenty years- late 1,500,000 tons were treated, which produced 128,000 tons of nugar, or about 8 per cent. Last year about 12,000,000 tons of sugar were crushed, which produced 1,500,000 tops of raw sugar, raising the percentage to 13. This ad\ance is due entirely to scientific treatment. The (production of dry colours, chemicals, and dyes in Germany fchows a corresponding increase in production and dividend-paying capacity. The greet increase of earning capacity is. due largely to the constant labour of trained men, who by application of their .technical knowledge have so cheapened production that they have succeeded in getting this trade out of the hands which previously controlled it. A great advance has also •been made in the scientific-instrument industry. The value of the exports from Germany of scientific instruments in the year {1898 was about £250,000— three times what it was in 1888— and the work gave employment to 14,000 people. These are a few of the inanv instances showing the close connection" between the scientific education of the German people and their commercial prosperity —M. Santos Dumont. in an art'ole in the ; North American Review, claims that ho is ! much more of an aeroplanist and much less of a balloonist than has been asserted. True, lie relies on the displacement of air by (hydrogen to rai«o the greater part of his airehip's weight. But as the last few pounds are actually raised by the motion of his propeller it is on this that the ascent and descent of the whole depend, and so far the machine can fairly claim to "fly" and not to "float." From one point of \iow the -tubular bag of hydrogen may simply bo regarded as an aeroplane made of the lightest materials that yield a tense surface. As against men of Ecience who insist that the pressure put on the plane by the propeller should be sufficient to make the freight of the plane itself irrelevant, M. Santos Dumont points plausibly to those originals of all flying, the wingfi of birds. Their bollqw quills embody tho very maxijjium of lightness that is consistent with firmness, and even thoir very bones conJtain air where ours contain marrow. Convinced of the soundness of the "flying" conception for which the aeroplane stands, he floes not think that the union with it of the "floating" conception of the balloon is by any means a transitory makeshift. The air6 1jip that is, the blend of the two — will always have tho advantage over the most perfect aeroplane tJtfough its greater cany-

ing capacity The aeroplane will replace it for quick journeys over long distances — for instance, from Dover to Calais : but for long journeys, for commerce, or for war, the airship will remain in use. An airship of the length of the Deutschland steamer, and built on the plan of that <r No 6"' airship with which M. .Santos Dumont sailed over Paris, could, he claims, carry a thousand passengers of his own weight, motor, petroleum, and all from New York to Havre in two days.

—An ingenious apparatus for estimating the amount of dust in the air has just been devised by Karl Arens. It consists of a glass tube loosely packed v. ith cotton wool and connected with an aspirating apparatus on the principle of bellows. After the tube /id tho wool have been perfectly dried, they arc weighed, and then a given volume of the air to be tested is drawn through, carrying with it its quota of dust and moisture. The tube is then allowed to stand over strong sulphuric acid for 24 hours, or until the moisture ib evaporated from tho wool. The tube and its contents are now weighed again, and the increase m weight represents the amount of dust in thr given volume of air. A great many expenments have been tried with the new instrument, and -among the results are the following, which show in milligrammes the amount of dust per cubic metre found in the an im the places mentioned: — Laboratory, 1.4; schoolroom, 10 : horsehair factory, 17 : .sago factory, 17 and 15; woollen factory (picking room), 7; woollen factory (cutting room), 20; flour mill, 22 and 28; iron foundry (15 |to 20 workmen), 28 : iron foundry (not previously lued), 1.5; iron foundry (few workmen), 12; iron foundry (during interval). 8; stuff factory, 72; snuff factory (before trrimliug), 16: cement works (during work), 224; cement works (in an interval), 130.

— Having already made effective use of peat moss litter in the preparation of certain food stuffs the Germans arc now tinning their attention to the employment of sawdust for a somewhat similar purpose. It is announced from Berlin that a German chemist has taken out a "patent for a new form of a-nimal fodder which has sawdust as one of its principal ingredients. The chemist to whom tho patent for this new food has been granted argues that farm j,to/>k always show a decided hkiug for young shoots, roots of shrubs, tree bark, and other food of tho banic nature, and taking advantage of this fact he had special experiments made with the object of ascertaining whether it might be posbible to utilise the sawdust obtained from fcuch wood as a food stuff. The results are «ud to have been so satisfactory that great things are expected of the new material, which, like the peat mo« already referred to. is meant to be chiefly used as a "drier" of the molasses now so laigely employed as a stock food in various paits of the Continent. — Farmers' Gazette.

— Cities might be altogcthei smokeless if some of the anticipations indulged m by Dr Oliver Lodge before the P.iimingliani University Engineering Soeietj could bo lva heed. Dr Lodge fajours a scheme by whi<h gas could be laid on to the town in huge mains, and distributed like tho water service. The Chcfelnre Elect ho Light Tom pany claim to be a pioneer compauy in thi? direction, being the firs>t to di-pcnse with steam. They used Monti pra«. and had entirely banibhed smoke. Mond gas will bo generated at the pits*' mouth, and will bp conveyed in pipes o\er long di-tancrs: it will bo u=ed in ga= ci.^inrs ami in fur naees, and the wasteful =tram oii<ri"ifv anil thg hidcoiii chimney will be thing* of tho psi-st.

— An inventor in Vienna i<- reunited t-o have succeeded m producing a sla<-F which is practically a nnn-i omlnctoi" of hfat. Wh'n a quarter of an inch thick, tin- ci - i-- 'aid to allow only 7 per cent, of mi. heat to pass through it, while plate-gla-s of tho '-nmo thickness allows 95 per cent, to pah- Such a glass should be excellent for the windows of dwelling-houses, particularly of sucji rooms as bay« a §outhern expos ure A ot fej

workrooms lighted from the roof. Venetian or any sort of inside blinds are of little service in keeping out sun-heat with ordinary glass panes, but non-conducting glass would keep the apartment cooler than even outside shades can do. IE should also keep rooms warmed in winter by refusing to conduct the heat out.

— The life-history of a hailstone is the subject of an interesting paper by Mr A. H. Bell in the excellent magazine of philosophy which was founded by the late R. A. Proctor. The beginning of each of these aerial snowball 1 - as they may be called, is a tiny atom of ci 'st or fluff which has been carried up on <ne of those strong ascensional currents or air-lifts, whereof the upper parts are visible as cumulus clouds, into the middle height. The embryo hailstone gets itp =hare of the condensed moisture of which the columns of the cumulus — as a rule we pee them fore-shortened — are. formed ; and. since the process of condensation sots fiee a large amount of latent heat and raises the temperature of the air, a =econd ascerding current is generated which conveys it to the bitter-cold cirrus levels, where it becomes a tiny pellet of snow. For a time it jigs up and down on the top of these air currents, much as a glass ball dances on the top of a water-jet in a shootuiV gullcrv : hoon<*r or later, however, it has t.'^eii to itself so many of the surrounding snow cr} stal.s that it is too heavy to reniam there, and slowly it begins to fall. As it dc-cends it rolls through strata of air differing very much as regards temperature and humidity: since, however, the surface is always below freezing point, it contrives to obtain a fresh layer of condensed and frozen moisture from each successive stratum. Direction shows that these layers are alternately dear and oqapue. When it passes through air tiiat is below the freezing point the moisture that settles on it freezes as clear ice : on the other hand, if the stratum is abo^e the freezing point, the now layer is opaque. When it is caught in an atmospheric whirl (as in a thunderstorm) it is rolled through the same strata again and again, and grous large that it is slung earthward from the edge of the wrack, and reaehe= the earth without melting.