Science Sittings

New Zealand Tablet, Volume XXXV, Issue 8, 21 February 1907, Page 35

Science Sittings

By *Volt f

Birds - Foretell Storms. - •Birds are endowed with a remarkable instinct — they never ' fail to return home long before 'it rains or a storm approaches. The common sparrow comes first.. From his nest he chirps warnings to his feathered j brethren of larger species than his own. A Powerful Explosive. ■ The most wonderful ah>d the most powerful explosive known is said to be chloride of r&trogen,. It is believed to be the only substance that will explode on coming -in . contact ' with _ a bright* beam of light, whether the beam be fromT an electric light or - the ,- sun. The Supply of Rubber. The fear that— 'the rubber supp.ly would not fill the demand in a few years is being dispelled by the "intervention of . the French Government, - which' is restricting the wholesale destruction of the trees,, and ,is planting specimens of the., hardiest rubber trees in devastated regions. Durability of Cypress Wood. Sections of "old. water pipes of cypress that had been underground and in use for nearly " a century were recently exhumed at New Orleans, and, to the surprise of all, the wood was perfectly preserved and as hard as when laid. They were part of the first ~ water works system of the city, and it- is thought the wood was from_ trees 100 years old when laid.' l How Mahogany Got- Its- Vogue. J - The real value of mahogany as"* a cabinet wood was discovered by a London physician in the latter part *of the seventeenth century. The doctor's brother was " • engaged in the West Indies trade, and on one occasion he brought over in his ship several logs of "mahogany as ballast, and suggested that the wood might be . of value as beams for the house the doctor was then building. The workmen, however, found that their tools were not equal to the task, and the logs were rolled • into; thef gaorden, out of the way. When a box was needed a carpenter had -one removed t*b his shop, but complained, as the others had done, that he- could not work' the material with his tools. The doctor became interested and ordered that" heavier tools be made, and - ' after a delay the box was finished, and proved to. be " so -handsome that a bureau was made up from another of the logs. This was handsomely . finished, and' was declared by experts to be so superior to other wood? .. that a craze for mahogany set in, largely fostered by ' the Duchess of Buckingham. Wireless Telephonic Communication. Wireless telephonic communication between Berlin and . London will be an achievement of the near, future, according to Professor Slaby, and he regards it as not improbable that he may ultimately be able to ring up New York,. There can" be no question as to the' success of his first effort to adapt the principle of wireless telegraphy to the more convenient process .of talking through tho air. Several officials representing the German" postal department were present when con•versation was transmitted by: the " new method from Berlin to Naueri, a distance of 25 miles. The instruments were similar in appearance to those used in the Slaby-Arco system of " telegraphing. The transmitting apparatus reached a height of 20 feet above the"~roof Oi a building in Berlin, which is in itself 70 feet in" height, and "the receiver had been placed- at the top of a' high tower. Messages spoken by the Under-Sec-retary of the Post Office -are stated to .have been heard " loudly and distinctly ' at Nauen ; the test was,, in short, completely satislactory, as was also another carried out later over a distance of three miles" within" the city area of Berlin. Professor Slaby says that much of the success of the' invention must be credited to his colleague, Count Arco, and to' the technical > staff of the Berlin Wireless ' Telegraphy- Company. It would appear that they have completely anticipated Mr. Valdemar Poulsen, the young Danish expert, who stated recently that he was -engaged on the problem of wireless telephony. ,- ...

A fine bronze statue of the Maid of Orleans is being erected in front of the Melbourne Public Library.