Science Siftings

New Zealand Tablet, 11 September 1913, Page 53

Science Siftings

By 'Volt.'

• Queer Facts About Colors. Experiments have been made in Europe to determine what color in a soldier's uniform is the least con spicuous to an enemy. Of ten men, two were dressed in light grey uniform, two in dark grey, two in green, two in dark blue, and two in scarlet. All were then ordered to march off, while a group of officers remained watching them. The first to disappear in the landscape was the light grey, and next, surprising as it may seem, the scarlet. Then followed the dark grey, while the dark blue and green remained visible long after all the others had disappeared. Experiments in firing at blue and red targets, made at the same time, proved that blue could be more easily seen at a distance-than red. The First Electric Railway. So far back as 1837 a car propelled by electric power was run upon the Edinburgh and Glasgow Railway, but the cost of producing electricity from batteries, the only means then known, was too great to allow it to be used commercially. The invention of the dynamo-electric machine rendered it possible to use electric power economically, and the first practical demonstration of applying this system to railway propulsion was at the Berlin Exhibition of 1879, where a short line, designed by Werner Siemens, was worked with complete success. In 1881 a permanent electric tramway, one and a-half miles long, was established at Lichterfelde, near-Berlin. Land and Water. In our schooldays we learnt that water covers threefourths •of the earth's surface, and land the other fourth. This statement dates back to a time when very little was known about the distribution of land and water in the Polar regions, and needs to be considerably revised in the light of recent discoveries. Taking account of the results of the latest Polar expeditions, Professor Wagner estimates that the ratio between land and water is 1 : 2.42; in other words, that about three-sevenths of the earth's surface is land, and the rest water. This estimate assumes that only 10 per cent, of the surface north of latitude 80deg. north is land; ah assumption that may be considerably modified, says the Scientific American, by the explorations of the great unknown region north of British America and Eastern Siberia. A Speaking Cinematograph. A new machine has been invented which not only takes and produces animated photographs, but records photographs of the sounds and reproduces them in unison with the pictures. So far there has been great difficulty, when using the gramophone or phonograph and cinematograph together, in getting the actions illustrated on the screen and the voices of the singers or actors to synchronise, but with the new invention this difficulty is entirely overcome, and the sounds are produced by a . new process which entirely' does away with the mechanical methods employed hitherto, so that the sounds are claimed to be natural and free from the hissing and scratching associated with the needle or stylo of mechanical reproducers. The voice is made to act on a sensitive electric contrivance which regulates the light falling upon a moving strip of film, passing through the camera at the side of the film on which the pictures are taken. Two photographic records are thus obtained— of the animated pictures, the other of the sounds. In the reproducing machine the photographic band of sound records is used to regulate the strength of a beam of light falling upon a highly sensitive photo-electric element, and this regulates the sounds set up in a powerful telephone which is connected with a large . trumpet. The sounds are produced entirely by means of this ingenious combination of photography and electricity, and are pure and natural, and the voice is reproduced at the actual instant shown in the cinematograph pictures.