Science Siftings

New Zealand Tablet, 23 March 1911, Page 547

Science Siftings

BY ‘VOLT’

Adopting Greenwich Time. The clocks of France are soon to be set back nine minutes, and, according to the law recently adopted, they are to mark the time in conformity with the time at the great observatory at Greenwich. Turbine Engine is Defined. There are probably few people outside the ranks of engineers who know what a turbine is. ‘ The best idea I can give of it,’ said an engineer, ‘is to liken it to those paper windmills which spin on the end of a stick, and which are sold to children in the streets. A turbine, in fact, is like a scries of these revolving wheels fixed one behind the other, only instead of being turned by the wind, it is revolved by jets of steam. The _ turbine wheels turn on a shaft inside a cylinder, in the interior of which are fixed a number of stationary blades which project into the spaces between each wheel. The purpose of these blades is to catch the steam and direct it on to the wheels at an angle where it will exert the most force. As the steam enters the cylinder it is caught by the stationary blades and deflected on to the blades of the first wheel, which are set turning. The steam then passes to the next, until all the wheels are set whirling and the ship is driven through the water.’

Accounting for Milk in the Cocoanut.

Probably everybody lias wondered at times what kind of stuff the ‘ milk 5 of the cocoanut is. One inducement generally held out by the dealer to the prospective purchaser is that the nuts are ‘ all milky.’ Recent analyses, however, have dissipated the delusion that the fluid has anything in common with new milk. It contains only 4 per cent, of solids, consisting chiefly of sugars 2.8 per cent., the balance being made up of mineral matter and tartaric acid. More than half of the sugar present is mannitol, the sweet principle of manna, which is sometimes found also in wine as a product of normal grape sugar. The question has been discussed as to whether it would be profitable to extract the cocoanut water for the sake of its cane sugar, but as this amounts to only one-tenth per cent., the process would not be commercially successful, in spite of the water being a waste product. Even if the water contained 5 per cent, of sugar, as some specimens appear to have shown, the recovery of this amount would be .unprofitable. The juice of the sugarcane yields nearly 20 per cent, of sugar. Inventor of the Thermometer. Thermometers seem to have been invented about the end of the sixteenth or beginning of the seventeenth century, though like many other useful inventions, it is not agreed to whom the honor of the first of them belongs. Boerhaave ascribes it to Cornelius Drebel; Fulgenzio to Paolo Sarpi, and Sanctorio claims this honor for himself, being supported by Borelli and Malpighi. But M. Libri, after bestowing a great deal of labor and research on the subject, maintains, principally on the authority of Castelli and Yiviani, that Galileo had invented the thermometer prior to 1597, and that Sagrado perfected it. There is nothing improbable, however, in thermometers having been really invented by several different persons, independently of each other, and much about the same time. It took many years before the instrument was developed in its present form. At first it was a very imperfect measurer of temperature, as air only was used in the tube. This was found to be open to the serious defect that the air was affected by every variation in the atmospheric pressure. The Florentine Academy, about the middle of the seventeenth century, began to employ alcohol instead of air, and this form was introduced to Britain by Mr. Boyle. A great defect in early_ thermometers was that they had no fixed points from which to estimate, relative temperatures. It was reserved to the genius of Sir Isaac Newton to suggest in 1701 those points at which water freezes or boils, and this has met with universal acceptance. Newton used linseed oil in his thermometers, but it was found ope,n to many objections. _ In 1730 Reaumur designed a spirit thermometer, in which the space between freezing and boiling points of water was divided in 80 degrees. This thermometer is still used to some extent in Germany. The mercury thermometer is generally credited ,to Fahrenheit, of Amsterdam, who described it to the Royal Society of London in 1724.