Progress in Science.

New Zealand Graphic, Volume XLV, Issue 8, 24 August 1910, Page 44

Progress in Science.

The Height of the Antarctic Continent.

©UR knowledge of the Antarctic continent is daily becoming more precise. Soon after Shackleton's memorable dash toward the houth Pole had furnished very important data in regard to the interior vf the continent, Charcot’s voyage supplied valuable additions to our knowledge of the boundaries of th» vast territory. The French expedition succeeded in surveying accurately a great many miles of coast line that had previously been entirely Unknown or only conjectural!y laid down. The results of these expeditions prove that the mass of land accumulated about the South Pole i«s even greater, in comparison with the other continents, than bad previously been supposed. The elements involved in this comparison include an estimate of area, and a determination of the heights of the mountain masses. Both of these elements require exact and comprehensive surveys. The problem was first attacked by Humboldt, at an epoch when our knowledge of the earth was very incomplete. Hence Hum--1 obit’s estimates of the mean elevations of the known continents above the era level, are far too low. This mean elevation is the height of a fictitious plateau obtained by distributing the mass of the continent uniformly over its surface, i.e., it is the quotient obtained by dividing the volume by the area. Humboldt's estimates of the mean elevations or continents are: Europe, 672 feet: North America. 748 feet; South America, 1,151 feet; Ada, 1.164 fret: entire known land surface of the globe, 1.664 feet. Except in the case of Europe, these values differ enormously from the more recent estimate- given below. This discordance thows the of thorough exploration and a ceil rate surveys, although a general estimate can he obtained from elements of a totally different character, es we shall see in connection with the Antarctic continent. Kruemmel, who was the next after Humboldt to attack the problem, estimated the mean elevation of the entire known land surface of the globe at 1.443 feet, a value which was still far below the truth. The later estimate of Lapparent, based on more complete data, was 2,000 feet, or more, while the more recent estimates of Murray. Penck. Lupan and De Lillo are still higher. Murray’s values, as revised by Penck, are: Europe, 91S feet; Australia, 918 feet ; North America, 1.968 feet, Foutli America, 2,066 feet; Africa, 2,132 feet; A-ia, 3.116 feet; general land surface, 2.312 feet. From these values, which appear to be very nearly correct, the total volume of the continental masses is computed to be about twentyfour million cubic miles. All of these estimates relate only to those parts of the world that were known at the epochs when the various estimates were made. The recent Antarctic explorations have entirely changed the face of the problem and have raised the Antarctic continent to the first place, which was formerly occupied by Asia. The exact ami extensive knowlidge which we now possess in regard to Ihr other continents is still lacking in the case of the Antarctic, of which we kaow only the few points that have l>een reached by the expeditions. Meinardus has endeavoured to determine the height of the Antarctic continent from meteorological data. From Hip distribution of atmospheric pressures and the ex< hangi of nia-ses of air between the two hemispheres, he concludes that, if the continent covers an area of 5.266.6'13 -qua re miles, as Bruce ami Kreummel assume, its mean elevation above stu level is about 6.660 feet, with a probable error of 060 feet. If thiis estimate is approximately correct, as the results of the recent explorations appear to indicate, the Antarctic continent is by far the highest mass of land on the globe. By the addition of this huge polar cap the mean elevation of the entire land surface of the earth b increased from 2,312 ft. to 2,706 ft.

Dying Pearls. In the Museum of the Louvre in Paris lies a collar of pearls at the point of death! Its death-bed is a plaque of velvet; and it is the large collar that was part of the personal estate of Thiers and onee belonged to his wife. It is simply set and has no. artistic value; its material value, however, is estimated at £12,000. It consists of 145 pearls in three rows, the total weight of which is 2,097 grains, the three largest pearls of the collar weighing 30, 39, and 51 grains respectively. This collar must "die’; every day it loses another degree of its lustre, ami in the course of the present decade it will become as dingy as a much-worn wreath of roses. Why? Because pearls keep their incomparable sheen only when worn by

women and come into habitual eontaet with the gentle, soft, and warm skin of the wearer. When, for instance, Queen Augusta died it was found that her magnificent strings of pearls were likewise in a persistent decline, and for the reason, indeed, that for many years she had not worn them on her bare neek (which fact was explained by her age) but only around the fabric of the neck of her waist. At that time a treatment of baths in sea-water was perscribed for them by experts; ami for several months, under obvious necessary precautions, they were sunk into the sea and thus recovered their old lustre. Ln fortunately the Thiers collar has been laid' on red velvet, and this eireiimstanee, too, can help to dull its shimmering surfaces day by day, for the colour also, produced by chemical means, exercises a slow but sure influence. Besides it lies too near a window, and so the rays of light, too, have an injurious ellect on it. The directors of the Museum of the Louvre have long deemed the collar one of their most precious curiosities; but now, in consequence of the evident steady diminution of its value, they would like to sell it and with the money obtained for it procure a few good paintings. Permission therefore, however, is refused by the executrix and chief heiress of the Thiers estate, and

consequently the jewellers of Paris consider the collar an object of experiment by which it will be shown in how many years a pearl can “die away” when nothing is done for its preservation. How long pearls “live,” that is, now long they keep their lustre, has not yet been ascertained, but, as many instances, especially in the successive inheritance of heirlooms, prove, some preserve their freshness through centuries in consequence of the habitual gentle treatment they receive. When treated thoughtlessly a pearl dies quickly. Detecting Compass Errors. 'The steel hull of a vessel is rendered magnetic during construction by the hammering of tiie metal, and every steel vessel has to have it compass corrected to counteract its own magnetic lines of force. The magnetic influence is further complicated by the load carried by the vessel if this load is magnetic or capable of being magnetised. The ore-carry-ing vessels of the Great Lakes experience great difficulty on this account, and the United States Hydrographic Bureau is endeavouring to teach pilots and captains of vessels plying in this trade how to cheek their course by means of the pelorus. The pelorus is an instrument similar to the sun dial, being provided with a gnomon and a graduated arc on

which a shadow of the gnomon is east. The instrument is set in a north and south direction, as indicated by the compass, and then by noting the shadow on the graduated arc, it is possible to tell by comparison with tables, furnished by the government, just how far from the north and south position the gnomon really lies, thus showing the compass error. <?><?> A New Industry. In the northern part of Archangel, which is the most northerly government of European Russia, a farm for the breeding of Kamschatka otters, blue foxes, sables, martens, and other valuable fur bearing animals, is being established by German capitalists. Tho soil and climate of this district are exactly suited to the animals, and the annual rental charge is only about 21d. per acre, so that the venture appears very promising at first glance. On the other hand, a large initial outlay is required. Tho farm contains 1,200 acres, is enclosed by a fence covered with sheet-iron, which has cost £13,400, but the burrowing propensities of the foxes and rodents will probably make it necessary to extend this barrier underground, at ft large additional expense.

To Connect Denmark and Swedoa* According to “Electrical Engineering,” a definite proposal has been put forward for the construction of a tunnel between Denmark and Sweden, starting at Copenhagen, and connecting up with Malone. Connection would be made on the way with the small islands of Ainager and Saltholm, and the electrio trains which it is proposed to work through the tunnel would run on the surface on these islands, in order to reduce the underground journey as much as possible. If the svneme is carrieij out, it is estimated that the trip could be made in 1J hours. <?>«•<s> The Value of Rural Telephones. Merchants in the Southern States of U.S.A, have awakened to the value of rural telephone lines, and are seeking to develop them, with a view to increasing their trade among the rural population. In certain sections they have made large contributions to aid the farmers in building their lines. <»<»<?> Building a Battleship. Time was when it took nearly six years to build a battleship in private yards in the United States; but tha construction of the Connecticut at the Government yard at Brooklyn set a pace which has steadily accelerated. The Mississippi, whose trials took place as recently as October, 1907, took 44 months to construct. The New Hampshire, December, 1907, was built in 36 months; the North Carolina (cruiser), January, 1908, in 36 months; Michigan (battleship), 1909, in 34J months; the Delaware (battleship), October, 1909, in 27 months.