Science Siftings

New Zealand Tablet, 20 August 1914, Page 49

Science Siftings

By ‘ Volt.’

Old Shoes are Useful.

In France old shoes are bought up in quantities by rag-dealers and sold to factories, where the shoes are taken apart and submitted to long manipulations which turn them into paste. From this paste the material is transformed into an imitation of leather, which is used for the manufacture of wall-papers, trunkcovers, and similar articles.

Imitation Silk.

Silk dresses are now being made from wood. There is the cleverly ‘mercerised’ cotton, for instance; but machinery and chemicals have gone a step even beyond that in rivalling the art of the silk-spinning worm. The process of making silk yarn from a spruce log is a remarkably speedy one, and the results astonish you when you see the wood thrown carelessly into a great vat to appear a few hour's later in shining- thread. The wood is first cut into thin sheets, after which it is put* into a tank for chemical treatment. It is chewed and mashed by the machinery and ‘digested’ by the strong chemicals until it closely resembles molasses in color and consistency. The solution is then forced through well-heated tubes, each with an outlet containing just as many perforations as there are to be filaments in the thread. Simultaneously it is sprayed with a chemical which fixes the thread, shrinking and hardening it. But to the wearer of silk, a garment made from woodpulp looks every bit as good as the product of the silkworm.

~■> P }[ &<• Eye Strain. One makes a great mistake by saying -that the eyes are tired and the retina or seeing portion of the eve is fatigued. This is not the case, for the retina seldom, if ever, gets tired. The fatigue is in the inner and outer muscles attached to the eyeballs and the muscles of accommodation which surround the lens of the eye. When a near object has to be looked at this muscle relaxes and allows the lens to thicken, increasing its retractive power. The inner and outer muscles are used in covering the eye on the object to be looked at; the inner one being especially used when' a near object is looked at. It is in the three muscles mentioned that the fatigue is felt, and relief is secured temporarily by closing the eyes or gazing at far distant objects. The usual indication of strain is a redness of the rim of the eyelid, betokening a congested state of the inner surface, accompanied by some pain. Sometimes this weariness indicates the need of glasses rightly adapted to the person, and in other cases the true remedy is to rub the eye and its surroundings as far as may be with the hand wet in cold water.

Life in the Ocean Depths. Sir John Murray, lecturing at the Royal Institution, on ‘Life in the Great Oceans,’ described the methods adopted to insure that the catches in the trawl were representative of the different depths examined, /and showed how marine plants and animals were adapted to their special environment, i Referring to the presence of bacteria, he showed that life could not exist in the sea unless the bacteria did their work on the floors of the ocean. In the warmer waters the processes of life were hastened, so that while in the Arctic and Antartic many individuals were found but few species, in the Tropics many species were found but few individuals. In the Saragossa Sea the fishes showed colorw adaptation, and it was there that the youngest of the larvae of the eel were found. • A common method of protective coloration was for the backs of fish to be black and the sides silvered, this making them almost invisible at a considerable depth. When the limit of light was reached, at about five hundred metres, the fish were red colored, but as they reached the lower depths the colors became more sombre. There were various modifications in fishes to facilitate floating in

the warmer and less viscous waters, and some fish which had developed air bladders had a tendency to fall upward from the lowest depths.