Science Siftings

New Zealand Tablet, 25 February 1915, Page 45

Science Siftings

‘ Volt.’’

The Brittleness of Glass. The brittleness of glass is due to the quick cooling of the hot substance. It is known that constant motion tends to rearrange the molecule in any substance, and a similar effect is observed when glass is boiled in a weak solution of salt in water and allowed to cool gradually. The toughness of the glass is increased very much, and the effect of the quick heating is less disastrous to it. This is easily applied to articles such as glass globes for lighting purposes, and prevents much breakage. Carbons From Tar. Carbons of high grade are now to be obtained from tar by a process invented by a Swedish firm. The powdered carbon will be pressed to form electric-light carbons or larger sizes for electro-chemical work. The method is based on the fact that finely-divided carbon makes up a large percentage of the composition of tar and is what gives it the black color, this being due to the carbon particles suspended in an otherwise dense and transparent yellowish-brown liquid.- A process is used for separating the carbon from the liquid, and it can then be moulded into any desired shape. . , Piano Touch. It is usually considered that no mechanical pianoplayer, however excellently constructed, can reproduce the exact efforts produced by human touch. From the analysis of Professor Bryan, it would appear that this belief must yield to scientific analysis. lie analyses the precise meaning to be attached to ‘ touch,’ and shows that it may be perfectly reproduced on a pneumatic piano by means of an auxiliary lever which operates directly on the bellows, and is regulated by a sliding weight gliding on the lever itself or by the direct pressure of the hand. The analysis is very thorough and scientific, and it is perhaps a mere confession of human weakness to say that it does not entirely convince one who has heard Pachmann play Chopin. Introducing the Telescribe. Among the remarkable exhibits to be shown at the Panama-Pacific International Exposition at San Francisco will be Edison’s latest invention, the ‘ telescribe. ! This is a combination of telephone and dictaphone, and has never before been exhibited at an international exposition. It fulfils Mr. Edison’s prediction, uttered in 1870, that perfection in telephonic communication would be reached only when means were discovered for combining the telephone and phonograph, in order that telephone messages might be properly recorded. When the receiver of the desk telephone is removed from the hook and placed in the socket of the ‘ telescribe ’ the acoustic connection of the dictating machine is made, and then the user takes up the small receiver, attached to a ‘telescribe,’ and begins conversation. In this way both sides of the conversation are recorded on- the telescribe cylinder, and communication with the central operator is shut off, thus preventing ‘ breaking in ’ on the line. The value of the telescribe is shown by the fact that the telephone system transmits 60 per cent, of all forms of communication in the United States, totalling fifteen billion conversations a year, a grand total in excess of the number of telegrams, letters, and railroad passengers in the same period.