Science Siftings

New Zealand Tablet, Volume XXXV, Issue 2, 28 February 1907, Page 35

Science Siftings

By »Volt'

A Valuable Find. What promises to be a valuable discovery in monazite; containing thorium, has been made at Kangaroo Island, South Australia. Thorium is valued at £1700 per ton. The precise .percentage of thorium.' is at present not definitely known, but experts say it is high. One expert states that the crystals found are the largest in the world. The interest of the discovery lies in the fact that thorium is used for the manufacture of incandescent gas mantles, the increase in "the use of which has been a factor in sending'up the price of thorium enormously of late years. Road-Making Extraordinary. ■ -" Some: experiments are at present being conducted in . road-making which should interest all concerned with the laying-out of new roads. The roadway selected for treatment is ploughed as deeply as possible. Furrows are then dug across the road from ditch to ditch, four feet apart. Cordwobd is then placed injbhe ridges ' thus formed, and - ploughed clay .is laid thereon in-lay-ers, caTe being taken to provide flues in order that the wood which is to be set afire will readily bum and bake the clay. When the firing is completed -the treated clay is rolled and compacted to eight inches in thickness. The clay hasi been changed hy the burning) into clinkers, which compact into a solid*- roadbed, which will not form mud. The cost is low, and while the wearing qualities of the road have not been ascer- - tamed, it is believed that it will iwear as well as other made roads. Where wood is dear it is thought petroleum might be substituted.. New Epoch in Wireless Telegraphy. A new epoch irOvireless telegraphy seems about to open with the Poulsen system, which was explained recently to a distinguished audience of scientific men amd_ others, under the presidency of Lord Armstrong, by, its inventor, who is a Dane. It replaces the present sparkling oscillator by an apparatus for producing continuous electric waves. This effects' a great economy of energy, aryd - has a further result of the highest importance to the transmission of clear, distinct, .and intelligible messages. An illustration is given from sound waves. A" pistol-shot near a piano would set all the strings in vibration ; -but a tuning-fork would make only that string of the piano give a sound which had a corresponding rate of vibration with a tuning-fork. So far telegraphists have had, as it were, ' to pick out a message from the strings all vibrating together and interference between different lines of ,- communication has been difficult -to avoid. ,As -the result of successful experiments the Poulsen system will soon 'be operating commercially ; and it is likely to affect the possibilities of wireless telephonic communication. When Forks Succeeded Fingers-. Table-foirfcs are a comparatively modem invent/ion. They have been ioi- general use only during the last few hundred 1 years. 'They were first *used by -the Italian® as early as the twelfth century \ but it was " not until the' end of the fifteenth that they came into general use. In other countries at that time the use of tableforks was considered^ a contemptuous- vice, and .in 1450 Marius praised the King of Hungary for eating" with his fingers without soiling his -clothes. In the sixteenth century forks were not used in Sweden, and at the end of the same' century they were novelties at the French court, where the French beauties soiled their dainty fingers in conveying their food to .their mouths. - - . Strange to say, Engiland " was one of the last " among the larger nations to adopt the., use of tableforks, * and Ben Jonson, in his play,- •' The Devil is an Ass,' says : ' The laudable use of forks is being brought into custom here as in Italy, to the sparing of napkins.' - - ~ , , It was not until Shakespeare had been in his grave for tjwenty years that forks came into general use in England. . - , . After an extended tour of twelve months, embracing several continental countries of • Europe as well 'asEngland and Ireland, the Hon. John Meagher, M.L..C. arrived in Sydney on February 8. "