SCIENTIFIC AND USEFUL

New Zealand Graphic, Volume VIII, Issue 24, 13 June 1891, Page 58

SCIENTIFIC AND USEFUL

SOME WATER POWER. According to Herr Japing, the hourly rate of water falling Niagara halls is 100,000,000 tons, representing 16,000,000 horse-power, and the total daily production of coal in the world would just about suffice to pump the water back again. AN ELECTRICAL CLUB. One of the latest proposed applications of electricity is a policeman s club that contains a galvanic battery. When the rowdy seizes the club, thinking to wrest it from the policeman, the rowdy receives an electric shock which astonishes and paralyzes’him, rendering his capture easy. A HAPPY’ ACCIDENT. One day, in 1830, when a working jeweller, Joseph Gillott, now the famous steel pen maker, accidentally split one of his tine steel tools, and being suddenly required to sign a receipt, not finding his quill pen at hand, he used the split tool as a ready substitute. This happy accident led to the idea of making pens of metal. A MOTH TRAP. A kind of moth or butterfly is said to have become so very troublesome and destructive in Bavaria that every possible means has been taken to destroy it. The most effective method consists of attracting the pest by j an e^e . ctr ' c light in connection with a blow fan, which draws the insects into the suction, pipe by air draught and results in millions of them being destroyed. FLAT ROOFS. 1 here is no doubt but the form of a roof has much to do with the draught of a chimney. The flat roof offers no resistance to the passage of air, but as the pitch is increased the current is more and more disturbed, until with a high pitched and many gabled roof it is broken into innumerable eddies, some of which are sure to curl down and force the smoke and gases in the flue into the rooms below. Chimneys on such roofs should be built higher than ordinarily. FELLING BY DYNAMITE. Some interesting experiments were made the other day in the vicinity of Copenhagen with tree-feeling for military purposes by dynamite. The object was to ascertain the saving of time and labour effected by this method, and the results were exceedingly satisfactory—far more so than is understood to be the case elsewhere. Trees of so much as three feet in diameter were brought down in some twenty to twenty live minutes, whereas the time occupied by ordinary felling would probably have been ten times as much. SKY SYMPTOMS. The blue colour. of the sky is due to the scattering of light by the infinitesimal particles of water-vapour suspended at great heights in the atmosphere, which are small in size compared with light waves. They decompose the white light, reflecting more of the blue and violet which have short wave lengths, than of the orange and red rays which have longer wave lengths. In countries where the air is pure the azure is deep, and still more so at <reat elevations, where the density of the air is less. The redness of the setting sun is due to the increasing density of the atmosphere, the rays having to pass through more of it and the proportion of foreign particles increasing ; the shorter waves, blue and violet are filtered out, and”o’range tints appear, these in their turn disappearing, leaving the last sunset tints red. Impurities floating in the atmosphere °^j arge Cltles cause the sun, at setting and rising, to appear EXPERIMENTS IN TIGHT-LACING. Experiments have just been made with a view of ascertaining the effect of tight-lacing on monkeys. Female monkeys were put into plaster-of-paris jackets, to imitate stays, and a tight bandage put around the waist to imitate a petticoat band. Several of the monkeys died very quickly, and all showed signs of injuries resulting from the treatment. The British Medieal Journal, in treating the subject at some length, proves that the constriction of the vital organs ot the body caused by tight-lacing is continually working mischief in the human subject. It commends the enlightened intelligence of a certain section of the fashionable community, which is discarding the use of the corset, and states that those who are continuing its abuse are work ing woe for themselves and their children. An English paper, commenting on these reflections, says that this & all undoubtedly very lamentable, but, as an expression of opinion, it considers that the most to be pitied are the monkeys. A DUBIOUS FEAST. Hungry men, says a traveller, eat many strange things when needs must. One night, during our wanderings in Australia, we supped on some ° larvre of beetles that the blacks found in a fallen tree. A big fire was kindled in the cave we had chosen as our lodging, and the larvre placed on the red hot ashes. After being turned once or twice, they were thrown out from the ashes with a stick, and were ready to lie eaten. Strange to say, these larva* were the best food the natives were able to offer me, and the only kind which I really enjoyed. If such a lara- is broken in two, it will be found to consist of a yellow and tolerably compact mass, rather like an omelet. In taste it resembles an egg, but it seems to me that the best kind, namely, the acacia larva?, which has the flavour of nuts, tasted even better than a European omelet. Ihe natives always consumed the entire larva-, while I usually bit off the head and threw aside the skin, but my men always consumed my leavings with great gusto. They also ate the beetles as greedily as the latva-, simply removing the haul wings before roasting them.