SCIENCE NOTES.

Otago Witness, Issue 2744, 17 October 1906, Page 75

SCIENCE NOTES.

—An engineer named Fisher, according Jo a despatch from Berlin. Germany, has '~ " taken out a patent for wireless eletJttieal ■ appliances by which steam will be aufe»! ' matically shut off in two vessels that arre approaching each other in a fog 'at a distance of from one-half to three-quarters

of a mile. t — The sapphire workings at Yogo "Jpulch, '" Montana, arc being gradually dey^oped ipto a great and permanent mining j in1" dustrv, says Mr George F. Kunz .in^a- to '' port on- precious stones, published by .the '""United States Geographical Survey. Taken as a whole, the Yogo dike is perhaps the greatest gem mine in the world. It is about four miles long on the surface, and, being a true igneous dike, descends to an indefinite depth. It is estimated that the entire content of workable sapphire-bearing rook would approximate 10.000,000 eubio ll r '^yards. A mining plant is now being erected " rr! which will quadruple the previous output h .sind make Montana sapphire mining c, very ?f important factor in American gem produc- "~ tjpn. The stones obtained are not of large They range from "culls," used for -_jt[a.ti-ii jewels and other mechanical pur- - .poses, to gems averaging, when cut, from "' Tjalf a carat to 2 ' or 3 carats, and rapel.v iip to 5 or 6. As gems they are brilliant, free from flaws, and of good colour, ranging from fight shades to the rich, deep •blue of Oriental sapphires. • The Yogo crystals have an advantage for mechanical uses over East Indian stones in their form, which is largely short prismatic or rhomboi fcedral, with flat basal terminations and * 'hence they need much less cutting for sucb purposes as watch jewels. The gems are Bent to Amsterdam for cutting.

— Marconi believes that within, a decade it will be possible to send a message through 80,000,000 miles of space. He ' thinks* that the first agency canable of ■reaching Mars will be the heliograph. „^Why? Because it is an accepted scientific '".fact that light carries a much greater dis4 ,trance than sound or its equivalent. -But, while the heliograph will be the path-finder .through the immensities of space, there is If^yery reason to believe that it will simply be the forerunner of wireless telegraphy as it is now being developed. It may occur to some people that Mars may not be inhabited by intelligent creatures who could understand or answer us. For instance,

our earth before the age of steam was '-;pot in a condition to be introduced socially to the other planete. As answer to this Marconi refers to Professor Lowell. Only ovveiy recently he succeeded in photogcaphJug the ao-called Martian canals. From their Btratgbtaess he is they are <not natural* bat the -work of 'intelligent . beings. Their* a'ttipejjdous size, he asserts, proves- that th» "diggers- are -not only, creatures of great size and strength,- but greatly advanced in the use of mechanical devices. Such beings could-easily communicate their .(answer to «mf- pianet.

—Do the world's great telescopes 6py out the limits of our universe? Are there

spaces in the rky beyond which there are no more stare? That is the question on .which the schools of astronomical thought are at present sharply divided. In the 'fine ,veil of star 3 which covers the heavens, as teen through a great telescope, a veil with a mesh so fine that the specks of starry flight in it number 150,000,000, there are Wholes and rifte and black spots; and soro*» '.of' them have been known to astronomers 'since she fifteenth century, and were de-

scribed in the eighteenth. They have wme*tini'J9 been expressively called "coal sacks," ■from their blackness; and what we want ito know Js whether Hersehel's phrase wae flight; when in examining one of them he eaic to his famooa sister, Caroline Herecbel: "Hier ist wabrhaftig em Loch in IHimmel" (Here, truly, is a bole in tb« i -heavens). Are they- holes, -or are they merely funnels beyond which, and beyond ,ithe|powers of any telescope, lie other stars almost incop.ceivably distant? Or, again, iare*"they patches of dark nebula non-lumi-nons, ."unelectrified," unlit? When the new atar'ih Perseus blazed into sight some years ,ago "the astronomers of the earth perceived the spectacle of a nebula, hitherto unperceived, being "lit up." Are there vast expanses in the sky which shut off light? Or, again, is there enough cosmic dust ifi the universe or a large enough number of dark bodies, planets, meteorites, and the-.Jiks to exclude the gleams of stars if thqce stars be far enough distant? To the mtai armed with a little knowledge an>d an intelligent curiosity the answer would seem to be an affirmative one. If there are at least eight dull planets to our sinning sun, surely the number of dark bodies jin the universe must transcend the number if the starry suns, as— to borrow a simile if .Sir Robert Ball — the number of horse- ' ihoes in a country exceeds the red-iiot imes. But, as Mr * J. E. Gore, F.R.ASS., las recently pointed out, this is not -the « tpmffrh of several astronomers, with Profeseor Simon Newoomb at their head, who frylieve that the holes in the starry veil real holes ; that beyond them are no Stare, and that when we look through them •we look beyond the edge of our universe. 4There is, strange as it may seem, no •positive evidence of the existence in the Sky o£ dark bodies or of any matter that groujd shut off the light of the most dis-jtan-fc' stars. 1g — Two university professors have disi Ijovered a chemical by which they are able lo ¥e^tere burned documents, such as notes, ledgers, and insuranea policies. Document* Ipirhich. are no longer decipherable, and '«hich crumble into ashes in ordinary lands, are by this new process restored ufficienHy to enable a perfect copy to be lade, . The restoration is made one leaf r sheet at a time, and the inventors are Forking night and day in the transcript f 'valuable papers destroyed in the San Trancisco fire. The documents thus re^ to'red are not durable, but last long enough to have a copy made. The courts are expected to recognise these transcripts fes legal. The chemical formula which •works this wonder is a carefully-guarded secret. — How to Tell Bad Coin. — A corresponi ent (says Ohambors's Journal) sends this tatement. made by the foreman of the ury it the trial of a coining case ~«t the )ld;Jßaii*y recently. He said: "If the nthoritie., will afcoot a fcugg°stion from 2 business mon who have, during the >cai. o vdiiafc *eith considerable amounts of -lhor yiiUf'-thefe is a most simple wav to dojwt'a base coin imirfd : ateiy. It is by aking the suspected com bet wren the fore- ' inger and thumb of the left hand, and with a gocd coin held between the forefinger and thumb of the right haiul, sharp! v to ij»b the "grained" edges of the coma to-

when the metal of the 6purious tom will almost at once shave offp and t'e think it is one that the public ought i> Jbe made aware of." The foreman added tfhat he had written to thrfee* Chancellors of the Exchequer, pointing out to them tha' they should not deprive the public I' of this simple test by continuing to issue S'ei'ow-n and threepenny pieces without "grained" edges. The Common Sergeant, atter making a personal test, w said that he 'qnito agreed with 'the suggestion of the jury that its usefulness ought to be known. } ' —Among the things destroyed by the San Francisco earthquake was one of the I most curious telephone exchanges in the world, the Chinatown exchange, which had about 900 Chinese subscribers. The plugs were "nof numbered for' subscribers, but were each assigned by name to its owner. Tne reason for this was that the names and letters of the Chinese numerals were so long.. Thus, though TsTo. 808 might be JMr Sang Fat ;| his number ( would be ir- ' Chinese "ta't'-uak-sofi-gow-bat," and could 1 not be printed in any shorter way. But more ruricus than this was that the names themselves did not appear on the plugs in the exchange, but in the Directory alone, and the telephone exchange operator had to remember, and did remember, which plug belonged to each subscriber; There were 16 operators, working in two shifts of eight each, so that each' operator had to keep in his mental vision a picture of rather more than a hundred plugs with the names attached. When one subscriber wished to call another he merely repeated his name to the exchange. Even with this curious system the service was quick and trustworthy. The Chinese were rather slow to adopt the new instrument, and it is said that not a few of them believed that they must blow into the transmitter to call the central office. The Chinaman would never men tion the dead, or sacred things, in talking over the wire.

—It is reported that a Hungarian chemist, who has been experimenting for many years in the production of optical lenses, has at last succeeded in evolving a new process in place of the solid glass hitherto utilised. He uses two shells of comparatively thin glass, enclosing a liquid of high refractive index between them. This is in reality an application of the old experiment in which a pair of watchglasses placed together and filled with water are made to perform, very imperfectly, the functions of a- glass lens. It is to be presumed that the value of the invention lies in the character of the liquid employed, for there is nothing essentially new in the idea. No particulars are given as to the character of this liquid, but it is at' once apparent that it must possess a number of necessary characteristics 'f it is to perform the work expected of it. It is eaid that the new lenses can be manufactured for more cheaply than those of solid glass, and that they compare favourably with the glass lenses in their oplical properties. It would appear that all the familiar troubles, such as spheTioal and chromatic aberration, can be successfully combated by the new method, which is believed to be applicable to practically all the optical instruments which at present depend uppn glass. The new invention should be especially valuable in connection with telescopic work, for the cost of ,the huge object-glasses for large instruments is a matter whose difficulty increases enormously as larger sizes are attempted* It is believed that the new liquid lens could with comparative ease be made in larger sizes than can possibly be obtained in solid glass with the necessary homogeneity. It is reported that a number of the new lenses are already in process of manufacture, and the optical world jwill await with interest further news of them. — Cham be re's Journal.

— Although the theory of wave- motion was commonly accepted, tie question still remained": Waves of whit? Slince the days of Huyghen* and Young the medium of transmission has been assumed to be ether, but the problem was to find the cause that explained the effect. This is the question to which science has given the answer when it now tells us that light-waves are waves of electricity. Sixty years ago Faraday made the memorable discovery that a beam of light could be generated by a powerful magnet. The real meaning of this result was missed at the time. Nineteen years later Clerk Maxwell predicted the discovery of electric-waves, and in 1888 they were discovered. Professor Hertz was studying the electric spark as produced by an induction coil. This instrument is made on tne principle that an electric current in a coil of wire, called the primary, sets up another current in a neighbouring coil, called the secondary. This eecondary coil giv^s an increased effect for every turn of wire it contains, the wire being very fine and wound closely. The result gained is no increase in the amount of electricity, but only a change in its condition. Its energy is concentrated just as the energy of a workman, when concentrated at the end of a lever, can remove mountains. The current from a single voltaic cell, with a prt«6ure of only two volts, when sent through a well-made coil, may give a pressure of a thousand volts. It is this high pressure which produces the spark in the secondary coil. Hertz discovered that every spark caused an electric- wave, and that this wave travelled through space with the same velocity as light — that is,' at the rate of 186.400 miles a second. With a rin^-shaped piece of wire, having its cads close together, but not meeting. Hertz ■0.-oukj "d«tect" the "waves They showed I'herti&oW-es in tiny sparks passing- across the eliort'- gap between the ends ef the wire ring He made use of sheets of metal to ascertain if reflection occurred, a-u 1 then went to different positions with his detector. The waves were actually leflected, and the detector picked them up. HerU not only reflected them, but refracted them thiougli prisms of pitch. He found, more•over, that there was nothing "solid." according to the "ordinary notions of solidity. His sparks- passed through wooden floon* and stone walls with as much ea«e as a bullet passes through a. hedge. He polarised them just as light is polanwrl— that is to say, instead of radiating in all directions, -the waves -took a transverse course lin pas«»ng through certain substances. He i diffracted them, getting the bands of prssj matic colouts which ordinary light produces [ when it passes through narrow slits. Later j jnve<=tis;ators have confirmed the«e di«I ecnerjp*.— T. P.'s Weekly.

Baiwrs of Poultry should rise Nrxrao ajtd 81.-te's Game xwo Poultry Meal, which i« composed of the best ground bones at d shell*, ■pecially prepared to meet the requirements oi the fast-inere«EiTsg poultry in'" s.i It i» made up u» 341b b*g«, »t 1» *d e*ch. A*!t you; •torrkctper lot &