Science Siftings

New Zealand Tablet, 21 July 1910, Page 1155

Science Siftings

BY 'VOLT*

Spiders' Webs. The strength of some of the spiders which build their webs in trees and other places in Central America is astonishing; One of them had in captivity, in a tree there, not long ago, a wild canary. The ends of the wings, the tail, and the feet of the bird were bound together by some sticky substance, to which were attached the threads of the spider, which was slowly but surely drawing up the bird. A Submerged Forest. It is not often that one hears of timber being dug out of the ground. It is, however, being done in the far east. At Annam in Tonquin an immense wood mine has been discovered. The wood was originally a pine forest, which the earth swallowed up in some cataclysm. Some of the trees are a yard in diameter. They lie in a slanting direction and in sandy soil, which covers them to a depth of about four fathoms. As the top branches are well preserved, it is thought the geological convulsion which buried them cannot be of very great antiquity. The wood furnished' by these timber mines is imperishable. A Very Useful Tree. The carnahuba palm of Brazil is the world's most useful tree. A department store tree you might well call it, for it gives everything from medicine to cattle food. Its roots make a very valuable drug, a blood purifier that is prescribed a good deal in the spring. Its timber takes a high polish, and is in demand among cabinetmakers for fine work. The sap becomes wine or vinegar, according to the way it is prepared, and starch and sugar are also obtained from this sap. The fruit of the tree is a cattle food; the nut is a good coffee substitute; the pith makes corks. There, can you beat it —medicine, sugar, coffee, starch, wine, corks, cattle food, lumber, and vinegar all from this one tree, the carnahuba palm? Electricity and Amber. The term ' electricity' is derived from the Greek word meaning amber. It was supposed by the ancients, that amber had power to attract straw and dry leaves. Mention is made of this by Theophrastus as early as 321 B.C. No doubt he founded his conclusions on the fact that amber when rubbed vigorously does develop electrical phenomena. Amber is a sort of fossilised resin, yellow in color; it is found in large quantities on the Baltic coast, and sparingly in other localities near the ocean. Insects, leaves, twigs, and other objects are frequently found embalmed in amber, which helps to establish the theory that it is an exudation from the pine tree. How Finger Nails Grow. It has been computed that the average growth of the finger nail is 1-32 of an inch per week, or a little more than an inch and a half per year. The growth, however, depends to a great extent upon the rate of nutrition, and during periods of sickness it is retarded. It goes on faster in summer than in winter, and differs for different fingers, being most rapid in the middle finger and slowest in the thumb. According to the rate of growth stated the average time taken for each finger nail to grow its full length is about four and a half months, and at this rate a man of seventy would have renewed his nails 186 times. Taking the length of each nail at half an inch he would have grown seven feet nine inches of nail on each finger, and on all his fingers and thumbs an aggregate length of 77 feet and 6 inches. A Substitute for Leather. The discovery has just been announced in Scottish newspapers of a substance composed of a mixture of seaweed, carpet dust, goat's hair, Irish moss, and gums, together with some secret chemical ingredient or process, which produces a composition said to be a good substitute for leather and various other materials, as it can be used equally well in a fluid, pliable, or hard state. It is admitted by the discoverer that his composition is not equal in quality to the best materials imitated; but he claims as to leather that it provides an excellent substitute for the manufacture of articles of the cheaper grades of goods. The product has already been made up into boots and shoes, and its durability successfully tested by policemen, postmen, and others whose duty involves a large amount of walking. Two or three thousand feet of belting in machine shops is also in use at the present time, to which purpose it is said to be especially well adapted, as it is impervious to oils and acids, is non-inflammable, and does not shrink under the varying conditions of the atmosphere.