Science Notes.

Oamaru Mail, Volume XXII, Issue 6792, 18 January 1897, Page 4

Science Notes.

ICE AT THE SOUTH POLE. According to Dr Croll's estimate, ihe ice sheet at the South Pole is at this age several miles in thickness, its upper surface being above the lino of perpetual snow, and therefore not capable of melting away during tbe warm eras succeeding glacial periods. Further, when such an euormous mass of ice is again incrusted about the earth's surface, as eome geologists believe may be the case in the process of time, the consistent supposition is that as soon as it begins to yield once more to the influences of a milder atmosphere, as its counterpart did ages ago, the same process of flooding large areas of the earth will be repeated, and the same remarkable evidences of the presence cf seas and oceans that no longer endure will be left behind. The theory entertained by Alfred R. Wallace is much to the point, namely, that as a past glacial age was melting into the tertiary period, the seas in the northern hemisphere covered a much larger area than now, and extended across Central Europe and parts oE Western Asia, and the Arctic Ocean was likewise enlarged. It is well known, by geological evidences not admitting oE any question, that the lowlands of Europe were submerged, and that the Baltic, Caspian, and neighboring seas were simply a part of the vast Atlantic Ocean, instead cf boing land-locked waters as they are now. 51AES. The announcement by M. Flammarion . that the Trivium Chartontis of Mars had been seen doubled, as observed from Juvisy on November 10, is an interesting item of news in the astronomical world, and will be more so if similar observations were made at the same time elsewhere. The Trivium Charlonti3 is an object well known to students of Mars, being a dusky marking, of a roughly hexagonal shape, in which nine of the so-called " canals" find a meeting place. It is one of the most distinct of the faint, ill-defined, dusky spots, which, according to Mr Lowell, usually mark the intersections of the canals, and to which, as the discoverer of most of them, he has given the name of "oases." He, with some others, considers a canal to represent an irrigation system with a belt of country fertilised by it, but that scarcely meets all the features observed. Notes of transformations on Mars are always received with reserve until they have been Independently supported, but M. Flammarion is so distinguished an authority that corroboration of his observation will be awaited with eagerness. A NEW MOTOK. It is stated that a lady has devised and patented a detachable motor, which shall be alike available for a family carriage, a farm waggon, a common cart, a plough, a threshing machine, or a chaff-cutter. She has given her motor the figure of a horse, on which the driver may or may not sit; but obviously the shape does not affect the merit of the idea. VISIBILITY OF LIGHT. All information, however remote, as well as the results of experiments, how ever incomplete, which deal with the problem involved in the safety of life, or of our great sea-borne traffic, deserve to be recorded. The International Committee appointed by the Governments of the United S:ates, Germany, and the Netherlands, have just presented their report on the visibility of light under different atmospheric conditions. As might have been expee'ed, the results of the experiments made by tho different sections are not in complete accord, but they are not sufficiently wide of each other to render entirely valueless an opinion based upon them. Under ordinary conditions of weather, then, it appeara that a light of one candle power is visible at one and ahalf mile and ono of three-candle power is distinct at two miles A ten-c.indle power marks the range of visibility, at five miles, under the description "faintly," and " without difficulty." From this we see that the distance at which a light is visible decreases at a smaller rate than the inverse of the square root cf tho power employed. Rain or fos will, of course, greatly affect these results, and in-lhis respect the figures presented by the German representatives are of greater value These show that a light visible at one mile in a clear atmosphere requires an addition cf 50 per cent, to make it equally distinct, at tho same distance, but through heavy rain.—Shipping World. A'T.tyi.f.m: motor car. A firm of Italian engineers has recently constructed some small cars which are propelled by motors driven by acetylene gas. The charge consists of acetylene gas dissolved in fifteen times its volume of air, and with this mixture it Ins been found unnecessary to use water for cooling the cylinders. The method of igniting the charge has not, however, been made known. According to the Gastechniker, the motors maintain a speed of 600 revolutions throughout a working period of fifteen hours. The weight is only about 201b ; and 0 S brake horse-power is developed. The cost of working is said to ba about 6 G:l per hour. The Railway World. I HON" ,\NP STEEL. The new process for the direct production of iron and steel from the ore, which is being introduced in Sweden by Dr do Laval, is said to consist in mixing pulverised iron ore with carbon, probably in the form of pulverised peat, and subjecting the same in some form of a rotating cylinder to heat, after which it is brought into contact with an electric arc of immense power, which reduces the ore to metallic iron, says Industries and Iron. The melted iron then flows into a large and highly heated furnace, where it can either be manufactured directly into steel or cast in any suitable form for further treatment. Dr de L-»val commenced his experiments something like three years ago at Trollhattan. It is said that Dr de Laval has purchased one side of the entire water-power at Trollhattan, which is made up of four falls, yielding an aggregate horse-power of from £O,OOO to 70,000. He has also purchased at considerable expense very much larger water powers in the north of Sweden. SANITITIOX AND I!l"MA>" LIFE. In a recent lecture on what sanitation has done for human life, Pro. Brewer, of Yale University, said that no one doubts that human life has been prolonged by the application of science in the last fifty years. How much, mathematically, this amounts to, in years, in per cents, is an unanswerable question. We can never have the data in figures. Even if we had our vital statistics completed for that ! period, men would differ as to the relative ! value of the several factors in this proi blem. Oar great cities would not exist—they could not exist —without tho aids of science. We have had an ancient Egyptian and Greek and Roman civilisations, which were pigan, and Ir,inr Chustian civilisation, and all were powerless to convert practices. Between the epidemics that raged from time to time and the high death rate in the best of years, the population of Europe, as a whole, probably scarcely increased at all for 1000 or 1200 years. This century came in without a single city in Christendom with a million of inhabitants. Paris had in ISOO but 548,000 ; London and its suburbs in 1801, 864,845. The other great English cities had less than 100,000. Great cities could not endure then. First, the people coald not be fed. Then, most of tbe population had to be fed and food produced within 20 miles of the place of consumption. Science has now made it possible to transport food half-way round tbe globe, and has discovered new methods of preservation as well. City population was not self-perpetuating. Man died off; the death rate was continually high, and from time to time there was death by pestilence, Even where there were

sewers, they were to drain the ground of water rather than to carry away sewage. No cities are made nearly as healthy as the country. WOODWAKE FOB. AMERICA. The exportation of wood and wooden ware, lumber, wooden boxefe stave B and shingles, from the United States to foreign countries —chiefly England and Canada —amounted in value last year to more than 20,000,000 dollars. The importation of wood and wooden manufactures of all kinds amounted to 17,000,000 dollars, showing a small balance on the side of the United States.