Science Siftings

New Zealand Tablet, 19 January 1911, Page 127

Science Siftings

BY 'VOLT'

New Wireless Service Begun. The other day William Marconi personally directed an exchange of communications between the wireless stations at Coltano and the stations at Clifden, Ireland, and Glace Bay, Nova Scotia, thus inaugurating a new service by which it is expected the rates of wireless dispatches to America will be greatly reduced. Later Mr. Marconi went to San Rossore, where he was received by King Victor Emmanuel, to whom he made a lengthy report on his recent experiments. Artificial Daylight from Vacuum Tubes. Mr. D. McFarland Moore, the inventor of the form of vacuum-tube lighting most commonly seen, has a fine contempt for electric bulb and arc lights. They are ' simply refinements of the torch of the primeval savage, or the common candle,' he said in an address before the Franklin Institute, in Philadelphia. Their light depends upon the heating of minute particles to the glowing-point, so the amount of light depends upon the amount of heat, and even so, ' their scale of color and brightness is limited.' ' Moreover, they are far from economical and transform into light, even in their most improved form to-day, only a very small percentage of the energy contained in the coal that is put under the boiler. They may therefore justly be described as primitive and inefficient even in their present highly developed form.' China's Mineral Resources. China's resources of coal and iron are among the largest and most favorably situated in the world. The extent of the great coal fields has been put at 200,000 square —about twice the area of France and more than seventy times the aggregate extent of all the coal fields of Britain. Of the quality of the deposits much has yet to be learned, but the distingushed German geologist, Baron von Richthofen, reported many years ago that the anthracite and the bituminous varieties were equal to the best produced in Europe. It is expected that very soon Chinese coal will be delivered at far eastern ports at prices with which no other coal can possibly compete, and that China in consequence of this development will become a large exporter of iron. Mammoth Gates for the Panama Canal. There will be forty-six locks or sets of gates in the entire Panama Canal. Each lock will consist of two gates or leaves, hung from the sides of the canal, meeting snugly in the centre of the canal when closed. Each leaf will weigh about 600 tons, and will be 65 feet wide by 77 feet high and 7 feet thick. They will, of course, not be solid, but will be diaphragm work and have air chambers to assist in lightening the leaf. There will be 92 of these leaves, each to be composed of 18 plates or girders, with diaphragm work, all to be covered with steel sheathing, 7-16 inches thick at the top, gradually thickening until it reaches 13-16 inch at the bottom. Hanging these gates will be quite a feat. They will be set in a pintle at the bottom, and held by a yoke of massive design at the top. There will be twenty of these sets of gates at Gatun, twelve more sets at Pedro Miguel, and the remainder, fourteen, at Miraflores. About one-half of one of the shops at Rankin will be given over to the fabrication of the structural steel work of the Panama Canal. The Mighty Amazon. Only the mariner can tell the place where the Amazon really has its mouth, because the opening it has made on the eastern coast of South America is so wide that it extends over one hundred miles. A long distance before one comes to the mouth of the river, however, one is really sailing on the waters of the Amazon, because they force their way so far out into the ocean. They say that three hundred miles out at sea, off the mouth of the Amazon, you can hoist a bucketful of fresh water out of the ocean from the deck of a ship, such is the quantity of its water that flows from that gigantic basin. Long after you have entered the actual river, and have its banks to north and south of you, if you are in mid-stream you will still be out of sight of land, such is the breadth of the vast channel. The river stretches far into the ocean and far up the country. Take a map of South America and look out a place called Iquitos. It lies four-fifths of the way across the Continent from east to west. Yet from Iquitos there is a fortnightly service of ocean-going steamers to Europe which descend some three thousand miles of the river before they reach the sea.