Progress in Science.

New Zealand Graphic, Volume XLVII, Issue 5, 31 January 1912, Page 46

Progress in Science.

Elasticity of the Shull. Fortunately the human shun, although composed of bones, is elastic —much more so than one would think. The average male adult skull, in fact, is so elastic that it may be compressed laterally in diameter by a blow or by pressure, applied at the centre of area, at right angles to the surface at that point, by about six-tenths of an inch, recovering its original diameter and form, without breakage. The material pf which our bones are made is so highly resistant that a cylindrical piece only 0.00155 square inch in area (i.e., only 0.044 inch in diameter) has a tensile strength of 33 pounds avoirdupois, figuring out at about--21,300 pounds per square inch. As a matter of fact, bone has 50 pec eent. more tensile strength than hard wood, and a single bone fibre is shown in the Hygiene Exhibition, Dresden, supporting a weight of 11 pounds avoirdupois. -»<?><?> The Value of Norway's Water Power. According to ‘'Engineering,” Norway is estimated to possess an aggregate water-power, suitable for exploitation representing, when duly utilised, a total .of 4,000,000 constant horse-power all the year round, and in addition 1,500,000 horse-power can be reckoned with during three-fourths of the year. Consequently Norway has 45,000,000,000 horse-power hours per year, representing in coal about 30,000,000 tons. Putting the value of coal at 16/8 per ton, the above aggregate of hydraulic horse-power hours represents a sum of £20,000,000 annually.

Counting the Stars. A tremendous task, that of counting the stars up to the 19th magnitude, has been undertaken by the Dutch astronomer Professor Kapteyn, who has collected all the material furnished by the most recent discoveries. Stars of less size than the 14th magnitude are found in millions in the milky way, and the work of counting them from photographic plates can best lie described as similar, to counting blood corpuscles under a microscope. Professor Kapteyn places the total at 842,000,000 stars, the average being 20,400 stars to the square degree of the heavens. He has further calculated that the total light emanating from all the stars is equal to 2,384 times the luminosity of a star of the first magnitude. According to the Dutch scientist the boundaries o-f the universe, as far as human science has been able to penetrate, extend to 32,000 light years. <?>«>❖ A Coral Garden. A visitor to North Queensland thus describes a trip to a coral reef in the neighbourhood of Cairncross Island. "Have you ever taken a stroll in a coral garden? No. Well, you can have no idea of its beauty. Crimson, heliotrope, gold and green, lie the wonderful sea flowers, and under a mass of what might be considered the marine equivalent of ‘curly greens,’ an exquisite little fish, rich crimson with dark brown bands, darts out panic-stricken, and rushes round and round the miniature lake. But we have no mind to more than admire him, and finally’ he shrinks’ back again to his crinkley stronghold. Sea cabbages there are many, and the variety of slugs and their size would strike terror into the heart of the gardener on terra firma.”

In Search of Water. Striking instances of the efforts made by plants to obtain water were given by Professor Henslowe in a lecture to the Royal Horticulture Society recently’. “A poplar tree at Turnham Green,” ho said, “sent its root down thirty feet, finding its way underneath a wall, and then passing through the bricks of a well to reach the water. A botanist at Cape Town found a plant which went down 40 feet in order to reach water. Plants found in the little valleys or water-courses in the desert have little top, but long, narrow roots, the reason being that there is water below’, and the plants try to get at it. Dry situations tend to produce wood,” said the professor, showing specimens of convolvulus and heliotrope which had lost their herbaceous character and become shrubs. “Many bulbs grown in our gardens came originally from South Africa, ■where they have been traced to a lake now dried up, showing that, though originally water plants, they had adapted themselves to the new conditions.” <•> <s> <S> Sociable Stones. “Travelling stones,” from the size of a pea to six inches in diameter, are foul’d in Nevada. When distributed on a floor or other level surface, within two or three feet of one another, they’ immediately begin to travel toward a common centre, and there lie huddled like a clutch of eggs in a nest. A single stone removed to a distance of three and a half feet, upon being released, at once started with wonderful and somewhat comical celerity to join its fellows. These queer stones are found in a region that is comparatively level and littje more than bare rock. Scattered over this barren region are little basins, from a few feet to a rod or two in diameter, and it is in the bottom of these that the rolling stones are found. The cause for the strange conduct of these stones is doflbtless to be found in the material of which they are composed, which appears to be lodestone or magnetic iron ore.

An ElectrlcnHy-UKhted HfAelt ’

It appears from an American consul** report that a new life-buoy, which ha* been successfully tried, is to be introduced into the German navy. The apparatus, which weighs sJlbs, consists of two swimming cushions bound together by straps. The cushions lie upon the breast and back. The apparatus is provided with a small lamp, fed by a battery. The lamp can be fastened round the head with a band, worn on the forehead, so that in an accident at night the position of the person in the water can be seen at a considerable distance. The small electric lamp burns three or four hours, and with the reflector added, throws the light several hundred yards at night. In several recent tests of life-saving at night the victims of the supposed shipwreck, by the aid of the lamp, were easily discovered. The lifebelt can be buckled round the body in five seconds, and the lamp begins to shine as soon as the buckle is fastened. In case of catastrophe to warships the worth of the life preserver cannot be over-estimated, though in case of war its use would not be advisable. <S> <?> A Dog's Dislike for a Picture, A correspondent of the “Westminster Gazette” writes: —“Will you allow me to say, in answer to an assertion that dogs do not take any intelligent notice of painted portraits, that at one time we had an old English sheep-dog who always showed himself excessively exasperated by a portrait which hangs in. our dining-room. He constantly growled and barked at it, and if sitting back to it would glance over his shoulders as if he thought it was watching him, ami then growl and bark. On one occasion, when shut in the room, the servants found him in the chair below’ this portrait endeavouring to spring at it, while’ furiously’ barking; and there are scratches on the canvas still, witnesses to the truth of Leonardo da Vinci's opinion.” —