Progress in Science.

New Zealand Graphic, Volume XLIV, Issue 4, 26 January 1910, Page 45

Progress in Science.

Erection of the Fades Viaduct.

Cl F PIECE of bridge construction > I work presenting some noteworT~ l thy features has recently been carried out in France. It is known as the Fades Viaduct, and is designed to take the railroad across the iwide valley in which flows the river Sioule. ffhe present work is notable for two reasons, one of these being the exceptional (height of the masonry pillars, which are ibuilt in the valley, and in the second place for the considerable length of the central span. The viaduct has the form of a straight iron lattice-work bridge construction. It is carried upon two lofty piers and two abutments, the length »f the consecutive spans being 383 feet, 475 feet, and 383 feet. The flooring of the [viaduct lies at a height of nearly 440 tfeet above the level of the Sioule. The (height of the great masonry columns »f rectangular section is 304 feet, and [they appear to be the highest pillars for a bridge ibuilt in Europe up to the present, .The most difficult part of the work was ito make the junction between the over‘hanging halves of the central span. f This was carried out recently, and [the operation was performed with (remarkable precision. To make the (junction, the whole bridge had to be lifted off the two main columns by hydraulic jacks, in order to make up for ithe slight sinking of the two fore ends and bring these exactly opposite each other and in true line. After joining ithe ends, the bridge was lowered again jupon its supports. <£><£>■s> Centenary of Gas Illumination. The centenary of gas illumination has evoked the customary inquiry, as to who [was its inventor. Some years ago, beIfore gas Limps, flickered in even London Streets, a Cornish miner had filled a kettle with small coal, and had been found lighting the gas he-got out of the spout. •But the real. inventor was the ninth Earl of Dundonald, then engaged in the manufacture of another new thing—tar. He made an enormous pile of coal for the sake of gathering the residuum. But the pile did not burn fast enough to please him, and he inserted a large air pipe to quicken combustion. The gas from the air pipe, to his astonishment, ignited. But while it frightened the

neighbour hood from its propriety, it quite failed to enlighten the Earl to the discovery of something even more useful than tar. > s><s>s> An Interesting Discovery. A recent, mission of the Chicago University resulted in the discovery of more than two thousand tablets covered with wedge-shaped characters (writing) dating five thousand years B.C. They are of every possible variety of size and shape. The most ancient look like a little orange on which the scribe responsible for the writing painted scrawlcharacters and left them for the sun to dry. That particular form of tablet was replaced by flatter discs, and. last of all, about four thousand years before Christ, came the perfectly flat, square, and rectangular tablets which were to hold their place indefinitely. Among the rectangular tablets of the ancients there ■were a few designed for special use. Some of them were for the use of school children. They were very much like the slates used by the children of the infant schools—nearly round. One of the most remarkable of those special forms was that of the tablet used for correspondence dating from 2500 years B.C. The clay slate was prepared and the inscription made as for all the- ordinary documents; then, when that part of the work was done, the slate, or tablet, was covered with a thin envelope, also of slate-clay, just as we use envelopes to-day, to protect the letter from curious eyes. A Wonderful Invention. It is seriously declared that Nikola Tesla, the well-known American inventor, ‘•'has practically perfected a new system of telegraphy and telephony, which differs from the present wireless system in th.ii it utilises as the transmitting agency, not waves of air, but the inherent conductivity of the earth itself. Space, time, and the elements it almost utterly disregards,” and, says the announcement from which we quote, Mr. Tesla is absolutely confident, from experiments which he has already conducted in Colorado and Shoreham, Long Island, that th? day when one may talk around the wcr d

by wireless telephone at a trifling cost ha* dawned. Moreover, the messages being sent underground, any pdssi'nli y of interference is obviated. Mr. Tes’a’s claims are very interesting, and that is why they are given such prominence. He boldly asserts that distance is no obstacle, as in the case of the air wireless,

that any ni:mber of receiving st thins may b? used, and that mu only will messages across and around rhe world become incredibly cheap, but that any man anywhere in the world may. by placing to his ear a receiver purchased for a dollar or two. bear un opera in Paris, Melbourne. Vienna, or New York. To an interviewer. Mr. Tes.a .-aid th t I.e

had proved from a station he had already established that the vevy powerful cur rent developed by the transmit ter traversed the entire glol>e, and returned to its starting point in an interval of eight yfour one thousandths of a second, th s journey of 25,(MX) miles being effected almost without any loss of energy.

A Fortune in Grains, Ten grammes or about cue third of an ounce radium chloride, equivalent t i one gramme of pure radium, is th* to. il output fur eighteen months of la? .1 >i.l:imsthal mines. After th? hospit i s tn.l scientific institutions have been sjp.i aed, the remainder w:ll be o'lcei ■ ’ sale at t 15.0 jr.utimo, or 15'. gr.i.iis.