Science Siftings

New Zealand Tablet, 24 March 1910, Page 475

Science Siftings

BY « VOLT'

Power of Niagara. The horse-power of Niagara Falls is said to be represented by five million, and only 5£ per cent, of this is utilised in an industrial manner. Of this 126,800 horsepower is employed in electro-chemical processes, 56,200 horse-power for railway service, 36,400 horse-power for lighting, 45,540 horse-power for various industrial services 12,300 horse-power is transmitted over more than 100 miles, 33,500 horse-power between 75 and 100 miles, 3100 horsepower between 75 and 100 miles, 3100 horse-power 50 miles, 79;640 horse-power between 10 and 30 miles, while 145,000 horse-power is used locally. Sand-soled Shoes. Appreciating the rapidity with which leather soles wear out, an inventor now comes forward with a ' rockbottom ' shoe, which he declares to be practically indestructible. His invention consists of a cement for coating the under-side of the usual leather sole with fine quartz sand. His process is said to leave the sole as flexible as ordinary leather, and yet there is no danger of the cement cracking and chipping off. The shoes are designed principally for out-of-door workers, and it is asserted that not only will the shoe resist the effects of wear, but it will enable the user to maintain a footing upon the most slippery surface, the sole presenting hundreds of fine points which will grip anything without slipping. A Costly Skate. - , Roller skating is older than most folk imagine. Joseph Merlin, a Belgian, born in 1735, a clever, inventive fellow, went to London in 1760 and exhibited his novelties at a museum in Spring Gardens, and afterwards in Prince's street, Hanover Square., Having made a pair of skates to run on wheels, he appeared with them at a masked ball given by Mrs. Cornelys, in Carlisle House, Soho. He was duly invited to display his skill. Having put on the skates he took a violin and began whirling about to his own music. One thing he had not studied, however, and that was- how to guide himself and to stop quickly, and the result was that before the performance had lasted very long he dashed into an immense mirror valued at £IOOO, smashed his fiddle to bits, and seriously injured himself. That appears to have dampened the spirit of inventors, for we hear nothing of other wheel skates for nearly half a century. A Valuable Discovery. Blotting-paper was discovered purely by accident. Some ordinary paper was being made one day at a mill in Berkshire when a careless workman forgot to put in the sizing material. It may be imagined what angry scenes would take place in that mill, as the whole of the paper made was regarded as being quite useless. The proprietor of the mill desired to write a note shortly afterwards, and he took a piece of waste-paper, thinking it was good enough for the purpose. To his intense annoyance the ink spread all over the paper. All of a sudden there flashed over his mind the thought that this paper would do instead of sand for drying ink, and he at once advertised his waste-paper as blotting.' There was such a big demand that the mill ceased to make ordinary paper, and was soon occupied in making blotting only, the use of which spread to all countries. A Little Lesson on How to Drive a Nail. not know how to drive a nail,' said' an expert carpenter. 1 When once he has realised this it is only a matter of a few minutes to learn how it should be done. The commonest mistake is the belief- that a hard blow with the hammer is more effective than several little taps, and the learner is inclined to admire the man who drives a nail all the way in with but one blow. This is where he is wrong four or five blows are much better than one. The reason is that one hard blow inevitably makes the nail rebound, ever so slightly, it is true, but enough to make it hold less firmly than it would if driven in gradually. The nail may be driven almost all the way with one blow, but several lighter taps are necessary to finish the job. 'Another thing,' continued the old carpenter, 'the beginner generally tries to drive his nails as perpendicularly as possible. This is another error, for a nail driven a little diagonally holds the parts together much more firmly than one driven perpendicularly. And in driving a nail diagonally it is even more necessary to proceed with gentle taps, for hard blows inevitably displace the surfaces that are to be held together.'