Science Siftings

New Zealand Tablet, 16 March 1911, Page 499

Science Siftings

BY ..-•VOLT'

» ? A Curious Clock. An extraordinary addition has been made to the exhibition of inventions now being held in Berlin. A shoemaker named Wegner, living in Strasburg, has sent'in a clock of the grandfather shape/ nearly six feet high, made entirely of straw. The wheels, pointers, case, 'and every detail is exclusively of straw. Wegner has taken fifteen years to construct this strange piece of mechanism. It keeps perfect time, but. under most favorable circumstances cannot last longer than two years. The Arch. The consensus of opinion among the learned is to the effect that the arch was invented by the Romans. Some claim that Archimedes of Sicily was the inventor, while there are others who would make it to be of Etrurian origin, but there can be no doubt about the fact that the Romans were the first to apply the principle to architecture. The earliest instance of its use is in. the case of the great sewer of Rome, built about 588 B.C. by the first of the Tarquin line of kings, a work which is regarded by the historians as being one of the most stupendous monuments of antiquity. • Built entirely without cement, it is still doing duty after a service of almost twenty-five centuries. A Boon to the Sea-sick. Ocean travellers subject to sea-sickness will rejoice in a device, recently tested with satisfactory results, tor controlling the rolling of ships in high seas. The idea is to balance the vessel by means of water compartments built in the form of a ' U,' running down the port side, through the hold, and up the starboard side. The water is controlled by a special device for balancing the upward swing of the ship. In a test on the Ypiranga and Corcavado,, of the Hamburg-American line, in the Buenos Aires service, it was found that a vessel which would roll as high as eleven degrees under ordinary conditions can be controlled to two degrees' motion by the use of the tanks-. Eating Away an Island. Strength is riot a thing usually connected with maidenhair fern, yet if its roots have not sufficient room they will break the pot in-which the plant grows. Blades of grass. will force the curbstones between which they spring up out of their place, and in a single night a crop of small mushrooms have iifted a large stone. Indeed, plants have been known to break the hardest rocks. The island of Aldabra, to the north-west of Madagascar, is becoming smaller and smaller through the action of the mangroves that grow along the foot of the cliffs. They eat their way into the rock in all directions, and into the gaps thus formed the waves force their way. In time they will probably reduce the island to pieces. Warned by Artificial Voice. Ships that pass the danger spots off the French coast will now be guided aright by the lighthouse bearing a wonderful resemblance to human beings. The new lighthouse, which is the invention of Dr. Marague, a Parisian ear specialist, is an exact imitation of the human throat and mouth, with an air pump for lungs. Teeth, lips, jaw bones, and all are imitated exactly, while a monster mouth and a compressed air device will .enable it to shout in tones of thunder to ships on the horizon. Dr. Marague's small models, hardly appreciably larger than the normal human mouth, can be made to utter a faint whisper, or give vent to an ear-splitting crv, not possible for man to make. Within a mouth six feet from corner to corner it is estimated that the artificial voice could be understood from three to six miles away, according to weather conditions. Motor-driven Plough. Engineering reviews the results of tests of motordriven ploughs, conducted by the Royal Agricultural Society. The tests were on 5-acre lots, and the time taken to plough the 5 acres, exclusive of stoppages, varied from 4 hours 56 minutes in the case of the McLaren, to 7 hours 45 minutes in the case of the two-speed ' Ivel.' That is to say, continues Engineering, the engines ploughed from approximately two-thirds of an acre to 1 acre per hour The plough used for all the engines was the same, and was a three-furrow plough, taking a total width of 80in and depth of sm. As this plough was hauled successfully at an average speed of 2$ miles an hour by the 'lvel' tractor, whose engine only did an average of G Go brake horse-power on the brake, it is quite clear that the large engines were very much underloaded. In order to make some use of their greater power the steam-tractors were driven a good deal faster than this, 3.38 miles average in the case of the McLaren. As a good deal of time was necessarily lost turning the headlands, the actual speed of ploughing was about 5 miles an hour in the case of the McLaren, .and it is mentioned in the report that at this speed the ground was very much broken up. The speed of even the ' Ivel' was probably faster than desirable for economical ploughing. Deducting the time the plough v was moving from the net time ploughing, the time spent in stoppages varied up to 1 hour 36 minutes. The/cost per acre ploughed is given in detail in Engineering/ the total varying from 3.11 s to 7.45 s per acre.