Science Siftings

New Zealand Tablet, 4 May 1911, Page 835

Science Siftings

BY ‘VOLT’

y v , • v . 1 To Telephone With Light Rays. Inventors have been busy for some years trying to make a practicable system of wireless telephony in which the medium of communication is a beam of light. The most recent device in this line is the invention of a Frenchman named Ancel, and is an improvement in an earlier form devised by Ruehmer. It is seemingly perfect in operation, but not likely to be used practically, because anything that cuts off the light between the transmitting and the receiving station also puts a stop to communication. Concrete Houses Not New. A series of cities has been uncovered by the Harvard exploration expedition in Guatemala, showing the remarkably advanced state of the vanished Maya civilisation. Terraced pyramids were houses of worship, and some of these indicate that they were ‘ poured ’ concrete, ante-dating Edison’s plan some twenty centuries. Several cities had been discovered previously, and the Harvard men found four more, with new facts as to the grade of civilisation reached by the extinct race of men. ' Wonderful Memory of Animals. The memory of animals running through generations is one of the astounding facts of science which it is most difficult to account for. Take any animal whose daily life entails a certain line of work, and put him in an environment where neither he nor his children unto the one hundredth generation wiU be able to carry out this work, then bring the remote descendant .into the original environment of his fathers and he will go about the duties of his kind as if he had been schooled in them. Recently it was found that some beavers were living in their villages near Avignon, on the Rhone. For at least 300 years they had hau no trees to fell for their dams, so for thirty generations they had burrowed in the banks and built mud walls about their lodgings with their tails. A Polish Count became interested in one of the colonies and removed a few of them to a forest-grown estate. Immediately the beavers established themselves by a stream, cut their trees and built their villages as their fathers had not been able to do for three whole generations. Cold Light. Where there is light there is heat, and where there Is intense light there is often intense heat, and further where there are also inflammable moving-picture films, we may have disastrous fires. It will be welcome news, therefore, that . a cold light ’ has been produced that can be used in the cinematograph, not only lessening the danger, but permitting the use of gelatine films, and relieving lecturers, managers, insurance companies, and audience of considerable nervous strain. Light without sensible heat has been hitherto obtainable in only two ways: first by exciting phosphorescence or luminescence electrically, especially in gases; and second, by straining out the non-luminous heatrays with some transparent substance like rock-salt, that does not transmit them. Of course, some heat accompanies all light; all we can do is to avoid or remove the ‘ dark heat ’ that usually accompanies the light rays. Neither of the methods mentioned above is in commerciil use for lantern-projection, although the ‘straining’ method has been so used in laboratories. Light accompanied by as little heat as possible is desirable for this purpose — witness some recent disastrous fires caused by lanterns using combustible films. A recent French inventor. Dussand by name, uses a light that flickers so rapidly as to be steady to the eye and yet remains dark long enough between its luminous periods to cool off completely. This he calls ‘ cool light.’ The End in Sight. Colonel Goethals has definitely stated before the House Committee on Commerce that the Panama Canal will be completed by September, 1913. The probabilities are that the great work will be practically completed some months 'before that time, for the Colonel has shown himself to be a conservative as well as eminently efficient engineer. He further stated that the cost will be 360,000,000 dollars, including all appurtenances. His appearance before the committee was for the purpose of urging the enactment of -legislation fixing the shipping tolls which will govern the passage of vessels through the canal. He asserts that this is essential, as the shipping interests of the world demand at least eighteen months’ advance notice of the rates, which certainly seems reasonable enough when one considers the amount of readjustment of traffic that will inevitably resuit from the opening of the canal. Incidentally, it is noticeable that less is heard at present of the amount of excavation accomplished and more about the material to be used in the locks and other construction. For example, word comes from Pittsburg that shipments of steel plates and fabricated material and castings are now going out to the Panama Canal on contracts at the rate of 40,000 tons a month.