Science Sittings

New Zealand Tablet, Volume XXXVII, Issue 8, 25 February 1909, Page 315

Science Sittings

BY 'VOLT

Why We Wink. No satisfactory determination has been made of the reason we wink. Some suppose that the descent and return of the lid over the eye serve to sweep or wash it off; others that covering of the eye gives it a rest from the labor of vision, if only for an inappreciable instant. 'This view borrows some force from the fact -that the record of ■ winking is considerably used by experimental physiologists to measure the fatigue which the eye suffers. The Orange Tree. The orange tree is regarded as a prince among trees and the emblem of genius. A peculiarity of this tree is that it bears fruit and flower at the same time. Its leaves are evergreen, and as it grows older it grows in beauty and fruitfulness, its blossoms filling the air with their .fragrance. It is indeed a fit emblem of marriage promise and hopes. The orange tree is considered typical of love, because, though its fruit is golden and its flavor and scent delicious, its rind is bitter, and, as every one knows who has experienced it, Cupid's dart causes pain. The orange is emblematic of gratitude as well as of genius and love. The Argand Lamp.

Argand, a poor Swiss, invented a lamp with a wick ' fitted to a hollow cylinder, up which a current of air was allowed to pass, thus giving a supply of oxygen to the interior as well as the exterior of the circular flame. At first Argand used the lamp without a glass chimney. One day he was busy in his workroom, and sitting before the burning lamp. His little brother was amusing himself by placing a bottomless oil flask over different articles. Suddenly he placed it upon the flame of the lamp, which instantly shot up the. long, circular neck of the flask with increased brilliancy. It did more, for it flashed into Argand' s mind the idea of the lamp chimney, by which his invention was perfected. "A Fowl's Egg. An expert, writing, in the Daily Telegraph, says that few persons except poxiltry-breeders (and not all of these) give much consideration to the chemical composition or physiological origin of an ordinary fowl's egg. If the shell is smashed, a glazy, semi-fluid mass is seen which is apparently shapeless, except that the yolk within it has the form of a flattened sphere. However, these two substances are destined, under proper incubation, to become a, living bird, which has to twist its way, unaided by its parent or anybody else, and escape from the shell (which, is only broken by a certain amount of pressure). "When the chicken appears it has bones and organisation complete. The contents of the egg consist actually of albuminate of soda (or what is known as the white), and the yolk, which ~ is largely composed of albumen and certain stimulating ingredients, which include phosphoric oil. This oily yolk -- is in the centre and the albumen surrounds it, and all that is necessary to germinate the contents of an egg from a breeding pen is warmth and moisture, which the broody hen or incubators supply. It should here be stated that the uncontrollable, propensity which leads fowl to become broody and incubate their eggs is due to blood vessels distributed over the skin of the abdomen, which become hot and sensitive at certain periods of the year. Relief is obtained by pressure, and it is probable that the frequent turning of the eggs in the nest — so necessary to. prevent the yolk from settling down — arises from a desire to get a cool surface to sit on. The albumen of an egg forms the flesh, blood, nerves, feathers of the young fowl, whilst the yolk is the material on which the fledgeling is able to subsist for two or even three days after it has emerged from its prison cell. The bones and scaffolding, or frame work, have still to be accounted for, for it has been shown that neither the yolk nor white contains an atom of solid matter. But the shell is left, and the oil above referred' to as containing phosphoric acid, and it is from these that the bone and framework are really formed, the real process being that the phosphoric acid of the yolk eats up the interior of the shell layer by layer, forming what is known as phosphate of lime for the bones, until the shell becomes so thin at the one point that the slightest pressure of the beak bursts it, and the perfectly-developed chicken makes its debut. It is interesting to note that had not the shell been thinned during incubation the exit of the young bird would have been impossible. The chemistry Df an egg forms an interesting study.