SCIENCE SIFTINGS.

Auckland Star, Volume XLIV, Issue 279, 22 November 1913, Page 15

SCIENCE SIFTINGS.

I . . ! ELEPHANT'S TEETH. The elephant has no cutting teeth, like most animals, but only a series of molars. These molars or grinders, as they wear ay vay, gradually move forward in the jaw, and the remnant of the tooth when the surface is completely destroyed is cast out in front. The same molar can thus ibo replaced as many as eight times. The tusks, -which are only enormously elongated teeth, can be renewed only once. This wearing process 'and the ejection of the stump of the tooth go on very slowly during the life of the elephant. I (Inly -one or two teeth at a time are in I use. or in view, in each jaw. There are . always other teeth waiting to pass for- | ward and begin their work, although I there is a limit to this succession, for. 1 when the last has come into use and : been worn down, the elephant can no ! longer chew his food, and must die of ] starvation, if he has not already suej cumbed to old age. WIRELESS TELEGRAPHY IX .MIXES. An invention lias been brought to light which will serve to considerably minimise the dangers to which every day the largo number of underground workers are exposed. A clever tierman subject, Ilerr .1, 1.1. Reinecke, of Westphalia, 'has invented a system of wireless telegraphy for use in mines. The system has been adopted at iJninington main colliery, in Yorkshire, where instruments have been fixed at two points and conversations have been carried on with the same ease I ;is is the case with ordinary telephones. i There is a portable instrument adapted i for use in tihe cage whilst ascending and i descending the shaft, and so a means of communication with Those above ground in time of disaster has been established. By this means rescue work will be conI siderably facilitated. for entombed miners will lie in direct communication with the pithead, thus being able to call for assistance and give directions as to their whereabouts and the best means of reaching them. j XOISES MADE BY ELEPHANTS. j Elephants are said to make use of a I great variety of sounds in communicating I with each other and in expressing their I wants and feelings. Some appear to be i uttered by the trunk, others by the j throat. The conjectures in which either means of expression is employed cannot be strictly classified, as fear, piea.surt*. wiint and othtr emotions uro sometime* apparently indicated by the trunk, sometimes by the throat. An elephan'' rushing upon an assailant trumpets shrilly with fury. Fear is similarly expressed in a shrill, brassy trumpeting, or by a roar from the lungs; pleasure by a continued low squeaking through the trunk or an almost inaudible purring sound from the throat. Want—93 a calf calling its mother—is chiefly expressed by the throat. A peculiar sound is made use of by elephants to express dislike or ! apprehension, and at the same time to j intimidate, as when the cause of some I alarm has not been clearly ascertained and the animals wish to deter an intruder. It is produced by rapping the end of the trunk smartly on the ground, a current of air hitherto retained being sharply emitted through the trunk as from a valve, at the moment of impact. The sound made resembles that of a lurge sheet of tin rapidly doubled. WOODED GANXON. Anyone familiar with the construction of modern weapons of warfare and the high explosives used in them would naturally suppose a cannon made of wood would be of little or no value as a weapon. Wooden cannons have been used with considerable success, nevertheless, in recent revolutions in Cuba, Haiti, ! and in the Dominican Republic. ! The wood used in the construction of I these crude weapons is a very tough ! variety, haying a twisted grain that curls I about the log in such a way that to split the timber with ordinary means is almost impossible. The best trees are selected and a piece of the log oft or Oft in diameter is cut. After the bark has been removed and the log made perfectly round it is swung up on a crude truss and a hole is burned into it from one end. The log is wound with strips of raw-hide cut from the skin of a steer. When the cannon is covered with the strips of hide another layer is wound on, and this i 3 continued until the wea-pon has increased several inches in diameter. After the log is covered and the bore is finished the weapon is treated to a hot draught, which tends to contract the hide binding, which becomes almost as strong as wire. These crude cannon have been used with success in a mimiber of instance?, and it is astonishing the number of times they may be fired before they burst or become otherwise disabled.

LARGEST EXTINCT AXEMAiLS. Some years ago Sir E. Ray Lankester told us "to be of good heart while contemplating the gigantic extinct reptiles of tie pact, for we 'had in the existing sperm whales, the Great Rorqual, and the whalebone whales, creatures bigger than any of them. That comparison still holds true, but the German expedition in search of the Dinosaurs of East ! Africa, ohe first fossil remains of which were found by Professor Fraas, six years ago. has afforded us a glimpse of reptiles much greater than any which are now "restored" in museums. The expedition sent out by the University of Berlin, is still at work in the I Hinterland, some rive days' march from the sea, and digging in the middle of a tropical and malaria-stricken wilderness is largely carried on by negToes. A preliminary report has been presented by i Dr. He'nnig, and, though no complete ji-keleton of any of the large Dinosaurs I has yet "been discovered, enough Las i been "found to prove that the largest African animals of that time exceeded iby far the mightiest of the North American Dinosaurs. It ie thought that th? largest attained almost twice the length of '.he DipiodoeuF, of which there i> a cast in the Natural History museums at South Kensington and which was SO I feet long. j The neck of this reptile. Gigantosaurus appears to have been at least 15 feet 'longer th.in that of the Diplodocus and a I good deal thicker, as ihe vertebrae aTe . nearly twice as high as in tihe American J monster. "Dull-witted giants," Mr HenI nig calls them, with necks nearly 40 feet j long and 0 feet thick, with length of legs i exceeding any known size. But in their neighbourhood wae a reptilian fauna, almost more diverse than the assemblage !of animal life in Africa to-daythe dragon tribe, large and small herds of armed Dinosaurs, terrible in shape; with mighty long epines along back and tail; i small, swift Saurians and otihers that ■flew, and the fearsome carnivorous repjtilns, which would attack anything exJcept perhaps a Gigantosaurue.