PEARLS IN COCOANUTS.

New Zealand Herald, Volume LXVIII, Issue 20868, 9 May 1931, Page 7 (Supplement)

PEARLS IN COCOANUTS.

VERY RARE OCCURRENCES. Those who cannot dive for pearls might, it is suggested, climb for them, for pearls have been found in cocoanuts. But a lifetime spent in searching would hardly bo justified by tho discovery of perhaps one pearl, for they are so rare that only one may be found in a century or more, says a recent writer. The first cocoanut pearl was discovered in 1741, and more than 100 years passed before another was found. A few have been found in Fiji, 0110 or two in the Torres Straits, and one was found in. Tonga about eight years,ago. The vegetable pearl is a real pearl, consisting of almost pure carbonate of lime, which goes to make up the composition of the oyster pearl. In the cocoanut the pearl is caused by tho seedling being unable to escapo through the three soft dents provided for that purpose in the end of tho nut. When these dents an as hard as the rest of tho nut the imprisoned seedlings cause a growth of carbonate of lime, which forms tho pearl in much tho same way as the oyster pearl is formed. The pearls are of a clear amber colour, and sometimes they are as large as cherries, though mostly they aro much smaller. In Java and tho East Indies they are found in the joints of bamboos, and occasionally in the wood of the teak "and pomegranate trees, probably formed by an excess of calcareous and siliceous matter in the plant. Although vegetable pearls aro rare enough to be the most valuable gems in the world, they are apparently of 110 special commercial value. In tho East Indies they aro valued very highly as charms, and the owner of one cannot bo induced to part with it, because he believes himself to be immune from nil evils while he retains possession of the pearl.

CHARTING THE SEAS. Each new year sees the recommencement by certain British naval sloops of survey work in connection with the hydrographic department of the navy. Their duty is to map out the highways of the ocean, and it is a proud thought that the ships of every maritime nation in the world are depending upon tl.e British Navy for their safe navigation. On the average, £IOO,OOO a year is spent upon keeping existing charts modern and preparing new charts. In some years 800,000 of these charts have been 6old, and there are agents in every large port in the world. In the year 1929, the latest for which figures , are available, 650,000 charts were printed. The sloops aro manned by picked crews, who receive extra pay. They are specialists at their work, and of the 1000 men nearly 100 are trained surveyors. The highest accuracy is essential, for a small mistake might lead to a great tragedy at sea. Even in " home" waters, where perfect mapping has gone on for generations, the work never ceases. Often the most vital work is done in " home" waters, owing to the ever-shifting sands and silt brought down by such rivers as the Thames and the Severn, on whoso banks stand large ports. New rocks are always being found, numbering more than 300 a year. In sorno years 100,000 alterations are made by hand to the existing charts at the hydrographer's department. MORE POWER TOR ENGINEERS. A new X-rav tube has been invented in Paris which produces much more penetrating rays than have been generated before, and works at a voltage of 400,000, or twice what has been considered practical till now. It will mean that engineers will be able to take photo graphs through thicker and bigger castings and metal specimens. REMARKABLE INVENTION. An almost-human servant of men in charge of power plants is a new valve which governs the flow of steam into large turbines in response to spoken commands. It must be operated over a telephone. When the despateller says, " Open," " Close," or " Stop," the valve obeys his voice. The voice actuates a set of electric relays, through which the electric motor that turns the valve is controlled.