Science Siftings

New Zealand Tablet, Volume 12, 12 November 1908, Page 35

Science Siftings

BY 'VOLT

How a Brick Chimney is . Built. When the brickwork' is completed a few feet above the ground, rods of iron are fastened around the chimney, resting on blocks of- wood. These rods are clamped against the bricK so tightly that they will sustain a very heavy weight. A scaffo'd is fastened to these rods, on which is a board platform.*" The chimney-makers stand on" this, and also have the bricks and mortar with which they jvork _on~it as well. When the? courses of brick are laid up so far that the scaffold is inconvenient to work from, another set" of rods are bolted around the chimney, and the scaffolding is elevated into its new position piece by piece. The bricks and mortar are raised from the ground by means of a rope passing over a -pulley inserted in a beam projecting above the scaffold. ' ' ' The North Pole. The distance from, the farthest point of polar discovery to . the pole itself is 239- miles. But this radius, though only 239 miles in extent, is covered by ice gorges and precipices of incredible difficulty, and frost is so severe that no instrument of human invention can measure its intensity, and it blisters the skin like extreme heat. The greatest progress that- has ever- been made across these wildernesses of storm, of fury and desolation,was at the late of six miles a day. Power of Niagara. What makes Niagara Falls' power possible is the fact that Lake Superior, Lake Michigan, Lake Huron, and Lake Erie, with a combined area of 90,000 square miles, representing the reservoirs of some 250,000 square miles of watershed, are situated 600 feet above the sea level. The great volume of water falling over the vast territory flows on. its natural course to the Atlantic ocean with but a slight descent until it is brought in fo^he narrow Niagara river, when, in the rapids just above the falls, it declines 55 feet and then, with a single plunge, drops into the abyss 165 feet below. Eminent engineers have computed that 275,000 cubic feet of water pass over the falls every second, representing in theoretical energy over 6,000,000 horse power. Kites and Flying Machines. I have been lately experimenting with a great kite supporting a simple platform of boards on which I lay face downwards' (says Hiram Maxim). The kite was attached to a captive Maxim flying machine. While the ordinary boats attached^'io this machine were g^ing in an ever-increasing circuit "a^ 20 miles an hour the kite swept around in a circle twice as large until,when at its height, it sped round at the amazing speeds of 80 miles an hour. The experiments demonstrate most clearly, that well-made aeroplanes placed at a slight angle above the horizontal and travelling at a high velocity " have much ■ greater lifting effect than A^as ever supposed. The results of recent .experiments are very favorable to those who contemplate making machines fly like a bird. Where the Water Goes To. Some people think that -all the water on the surface of the earth will eventually disappear by being absorbed by • the ground. As a matter of fact, all the rain water that filters .into the earlh comes to the surface again somewhere.. It goes down until it meets rock, through which it cannot pass, and 03 more' water is constantly coming down and pressing on, it, it has . to find a way. to escape to the surface. " In this- underground trip it makes for itself large openings'or underground rivers, and in these there is a great pressure. When ,jT well is sunk to tap one of "these water courses, the water rushes to the 1 surface, making what is. called an artesian well.