SCIENCE SIFTINGS.

Auckland Star, Volume XXXIX, Issue 183, 1 August 1908, Page 13

SCIENCE SIFTINGS.

TTTR ORIGIN OP MA3piALS. All those hairy, warm-blooded quadrupeds which suckle their young, and are hence called mammals, are the descendants of small five-toed ancestors about the size of a spaniel. This is equally true of the elephant, the gorilla, the horse, and the ox. In the sands and clays deposited since the t ; me of the chalk-sea, the remains (bones and teeth) of the ancestors of living mammals are found in great abundance. These sands and clays, writes Prof. Ray Lan kester, are called "the Tert : aries," am are divided into lower, middle, and nppe —whilst we recognise as "Post-Tertiar ies" (or Quaternary) the later formei gravel and cave deposits in which the re mains and weapons of the eave-mei have been found. The Tertiaries consis of a series of deposits amounting t< about 3000 ft in thickness, and they havi taken several million years in deposit ing—no one can say how many. SEEING NEW YORK FROM LONDON M. Armengaud, a clever French engi neer and scientist, who for years ha been experimenting with an inventio] known as the telespectroscope or tele phote, intended to extend the range o human vision to extraordinary distances says that he has so far perfected hi apparatus that he can now foretell tha the time is not far distant when a mai sitting in Paris or London will be able t< see what is going on in New York. Thi inventor says that in the -past fey months he has made remarkable pro gress towards the realisation of thi fascinating idea. His apparatus is liki the machine employed by Professor Kori for the telegraphic transmissions o photographs. He utilises the properties of selenium, and his method was inspirec by the cinematograph. STRENGTH OF GLASS. Glass is not a substance that we cai figure the strength of as we can a grea many other things with which we an familiar. It varies greatly in itself. Thi strongest glass, as a rule, breaks into th< greatest number of fragments. Compar ing the strength of thin glass with thick the former is relatively the stronger this is a thing very often lost sight o\ Then again, as to the difference betweej rough plate and polished plate, we fini polished plate the stronger. This is per haps to be attributed to the fact tha all these very fine surface hair crack are polished out. These only go int< the glass to a certain depth, and whei they are all or nearly all polished am ground off, there is less chance for som of them to form the basis of a crack and thereby the glass is* increased ii strength. Tests have been made am some formulae have been arrived at. A was to be expected, they show irregula results as to the strength of glass. SHIPS STRUCK BY LIGHTNING. Ships remote from the land are seldon damaged by lightning, despite the fac that some of the most awe-inspiring dis plays of atmospheric electricity are fre quently witnessed by those on board o them. Standing rigging, and even part of the running gear, is now made o steel wire, and this substitute for th old-fashioned hemp serves the purpose o a lightning conductor when the ship i not fitted with such an aid to safetj The electric current is conveyed dow: the wire rigging, and reaches the se: through the vessel's metal hull. Damag only occurs if the current be interruptei on its way to earth. In a comparative!; large proportion of instances the fore royal truck is struck by lightning, tha of the main less frequently, and thi mizen mast least of the three. Ver; serious casualties under this head oc purred to warships and merchant vessel in the days of wooden hulls and hempei rigging. Many vessels are now fittei with lightning conductors of approve! types, lest the wire rigging should fa.i to carry off the electric current. WHAT MAK.KS HAILSTONES. The formation of hail through electri cal action, according to the new theory o scientists attached to the Weather Bu reau at Washington, is an interestinj and f-ven wonderful process. The wini draws out a cloud into a long, narro\ strip. In that form, owing to the grea amount of surface, the cloud evaporate rapidly, and the rapid evaporation pre duees intense cold. Dry particles o snow are then formed, and these, by fri< tion with the water drops, quickly be come charged with negative electricity But the water drops themselves carr positive electricity; and since negativ attracts positive, a film of water i formed) upon ea-ch snow particle, and i instantly frozen into a layer of ice. At this thickness its outer surface r< mains moist, the water not freezing ther so rapidly, whereupon the electricj charge changes from negative to positivi and the particle is repelled by the wate drops and driven to the outer parts c the cloud. Here the increased cold l ers it with snow again, and the frietio charges it anew with negative electricity Repulsion is now once more change for attraction, and the particles rus back into the cloud, receiving upon thei surfaces another film of water, which i turned into second ice layers. Thus the growing hailstone darts zig zag through the clouds, piling up it alternate layers of snow and ice unti gravitation gains control, and sends it with a jingling crowd of its fellows, spin ning to the ground.—" Science Sittings.' . THE STORY OF GOLD. The earliest mention of gold is in thi second chapter of Genesis, where it is re ferred to as one of the metals of thi land of Havilah. Silver appears almos as early (says " Harper's Weekly"). Thi Babylonian civilisation, which, with tha of Egypt, ruled the Biblical world, ap pears to have had a silver currency " Shekels of silver." and "pieces of sil ver" are constantly spoken of. Gold wa used chiefly for ornament, its malleabilit; andl ductility making it the easiest o metals to handle. The mines which supplied the coinagi of the ancient world were in India. Solo raon's sailors brought gold from Ophii an unknown land, by main' thought t bo Mashonalnnd, in South-Central Africa where the ruins of pre-historical Semiti forts and mine shafts have been founc The Spanish conquest of South Ami rica flooded the world with gold and si ver. Prices rose tenfold during a cci tury. Before the discovery of America fat sheep could, be bought for a quartc (1/), and working men had lived sumj tuously upon 5 cents a day. The secon gr.?at influx of gold occurred during tli su'a of t'.e last century, when the mine of California and Australia were discoi cred, and since then there has been slow rise in the price of commodities, dv to the increase of tie precious metal hut on the whole the. rapid increase i population ha s kept pace with the ii crease of gold. ,