Science Siftings

New Zealand Tablet, 9 December 1915, Page 47

Science Siftings

—■ — ♦■■■— —_ By * Volt.’

German Artillery. Professor J A. Fleming, speaking recently at the London University College on 'Science in. War and after the War,’ said the great artillery which so easily demolished the forts of Liege and Namur consisted of a gun weighing 87 tons. A foundation of 37 tons was required for the carriage, 200 men were engaged in the manipulation of it, 25 or 26 hours’ work was needed to erect the gun, the shell weighed Bcwt and was sft 4in l° n g> 12 railway, carriages were required to transport the gun, it was fired by electricity from a distance of a quarter of a mile, and the cost of each shot was ■ about £SOO. Hard Water. Do you realise how hard water is when a boat sails ' through -it at full speed? Water passing at fifty miles an hour is not the limpid liquid we are accustomed to bathe in. If you put your arm overboard from a hydroplane running fifty miles an hour and strike a wave crest, the probability is that you will break your arm or wrist, because at that speed the water has not time to give, or even to change shape, and striking it is like striking so much metal, If a sworsdnian should enter one of the great hydraulic quarries where a stream of water, under enormous head, is used to wash down hillsides, and attempt to cut into one of those streams, his sword would fly in pieces without being able to penetrate the water. The stream is like a bar of iron. Ancient and Modern Guns. Mr. John B. C. Kershaw, F. 1. C. , discussing modern explosives and their application in Cossier’s Knyinecrim/ Monthly, states that it is difficult to realise now that at thesJbattlc of Waterloo the effective range of cannon was; less than two-thirds of a mile, and. that, as solid iron balls were employed, the destructive effect of artillery fire was confined to the individual or building hit. He adds that one round from a modern field gun - firing a Sin shell will do more material damage and cause more casualties than twelve hours’ firing with the form of cannon used in 1815. Mr. Kershaw states that when the Dardanelles were last forced by a British fleet (in 1807) the Turkish guns were firing stone shot, . and that in Nelson’s day naval actions rarely begad at \a range of more than 1000 yards. The writer predicts that the great battles of the future will be fought entirely on open country, and that, whether on land or ' sea, the.big gun, whenever it can be brought into action . under favourable circumstances, will be supreme. An Electric Bulb Barometer. It is an easy matter to convert a burned-out, iiican- * descent light bulb into a barometer that will fortell the changes in the weather with remarkable success (says an exchange). Place a discarded bulb under water in a deep basin, and after protecting the hands against danger from broken glass, break off the pointed bit of glass at the very end of the bulb with a pair of. pliers. As soon as an opening is made in the glass, the bulb will fill with water, which rushes in to take the •>' place of the vacuum. Tie a cord or stout string about the neck of the bulb and hang, it on a hook or nail. If the weather is to be fine, no water will drop from the hole at the bottom of the bulb. When the water begins to bulge out of the opening until drops fall from the bulb, you may expect a change in the weather. Atmospheric pressure governs the action of this simple barometer. ■ When the pressure increasesa sign of fair weather—it pushes the water back from the mouth of the bulb, and no drop can form when it falls, the water expands through the opening, until a few drops ■, fall. As lower pressure nearly always precedes a change of weather, a drop from the bulb usually indicates a coming storm.