SCIENCE.

New Zealand Times, Volume XXIX, Issue 4157, 17 July 1874, Page 3

SCIENCE.

How to Make Cheap Diamonds.—They really make diamonds in Paris, which are said to be a very near approach to reality. Here is the process : First, it is necessary to dissolve charcoal. Then follow processes requiring crystallisation—a mingling of pure water, a little carbonate of sulphur, and certain proportions of liquified phosphorus. Still, all this may not yield a thoroughly deceptive diamond. Another composition is made from silver sand, very pure potash, minimum calcined borax, and a form of arsenic, varied occasionally by a mixture of straw—a mixture for which an equivalent is paste, and which represents transparent pebbles burnt to powder, white lead, and other similar materials. Sometimes rock crystal is used, with borax acid from Italy, and nitrate of potash. Of these materials is composed' the false diamond, which figures so alluringly in the shop windows of the Palais Royal. Progress of Egypt.—The palmy days of Egypt, possibly as a result to the Oriental and Australian tx-affic via the Mediterranean and the Red Sea, seem to be returning to that country. According to recent accounts the quantity of land under cultivation is nearly five and a half million acres, and the px-oduc-tion of the Egyptian sugar fields since 1832 is increased by over five hundred per cent., which amount will probably be supplemented by an addition of fifty per cent, on the total as soon as the pi-eparations now going on are brought to a state of completion. Cairo has its gas and water works like European cities, and the originally narrow stx-eets are being replaced by wide and spacious thoroughfares ; there are already more miles of railway in Egypt than in all Australia. Four thousaxxd miles of telegraph are in constant operation, and three thousand more are either being constructed or ax-e projected. Pearls.—The value of a pearl is in px-opor-tion to its magnitude, roundness of form, polish, and clear lustre. Those of a symmetxical pearshape are in great demand for ear-drops and pendants. Very rarely, a pearl is found as lai-ge as a nutmeg. The most extraordinary pearl on record is the one mentioned by Tavernier, which was obtained at Catifa, in Arabia, a fishery famous even so far back as the days of Pliny. It cost the enormous sum of £IIO,OOO. It was pear-shaped, regular, and without blemish, two and a half inches long, and nearly one inch in diameter. The largest known pearl now in existence is that of the “ Hope collection ; ” it is two inches long and four inches in circumference, and weighs eighteen hundred grains. Spherical Motion and Plane Motion.— Professor Sylvester has x-eoently made a discovery, Nature says, which is likely to create some interest, not only amongst mathematicians, hut also amongst mechanicians and in-strument-makers. By means of a sort of lazy tongs, he has succeeded in converting spherical motion into plane motion, a result, we believe, hitherto looked upon as unattainable. This discovery will form the subject of a communication which Mi - . Sylvester is announced to lay befoi - e the London Mathematical Society at its annual general meeting on Thursday next.