SCIENCE NOTES.

Otago Witness, Issue 2817, 11 March 1908, Page 76

SCIENCE NOTES.

— The la.rg«sT known tusk is one from E&s>t Africa in /the possession of Sir E. J. I/ader, which measures 10ft 4in ]on^, with a a-i/th of ,and [weighs 235ib. The longest treks are' a'ttair from East Africa, recently in theopossession of Rowland Ward . Their respective lengths were lift siin"SHd, lift, j.nc their united weight 2931b. •> < — .In the production of- ' engraved plates by telegraph, Carbonelle, a . Belgium, use.-j a. picture prepared with, thick non-conduct-ing ink, and this is wound upon a revolving cylinder under a stylus in electrical connection with the telegraph line. The receiving cyhnd§r"'{s ctvrered with,, some soft metal 1 like lead, ovei- whicH is a stylus that gives a cut varying in depth with the intensify of the current from the stylus. The resulting pj»t© -is .ready for the printing press without change. ' — The Agricultural College, Tokio, recently announced that it had discovered a method of making pulp from bamboo grass (sasa>, for which the highest results are claimed. The bamboo grass is very common in Japan, and has been put to little use. It is proposed to teach the method to the Japanese farmers, and as it is hoped that pulp will be produced cheaply by it, both the farmer and the consumer should benefit. The matter is still under investigation, and no details are obtainable. — The common idea regarding autumn colouring is that frost causes the brilliant colour of the leaves. This popular fallacy is without any foundation in fact. Frost hat absolutely nothing to do with tinting of the leaves, except that it hastens their fa!;. Autumn colouring is due to oxidation, which is caused by the action of light and heat, somewhat similar to the rust on iron. With leaves it is due to the fact that in fulfilling their mission they become choked by their own excretions, and the acids thus formed are acted on by oxygen. — The laboratory of Nature is still more efficient than the electro furnace in the making cf gems. The artificial sapphires and rubies made in Paris have the composition of the natural stones except in the small amount of material added for colouring, but their difference snems to be considerable. The artificial sapphires are softer than the leal, lighter in weisrht. and they refract the j light, much less brilliantly. As a source of I blue colouring, chrome was tried unsuccessfully, and the process actually employed is a secret of the sapphire-makers. The red of rhe ritificial rubies. is given hv cobalt. — Hungfiry's postal department has de- ' | vised a flying letter-box to relieve the BudaI pest postmen, who are few in numbers and have hundreds of nights of stairs to climb daily in the great tenement houses. The new letter-box can be sent up to its destination from the ground floor by a spring. It at the floor required, and remains 1 there until it is emptied, or until the next delivery, when the postman can, by touching a spung, bring it down. Each box contains the necessary number of lockers, each fitted with a -safety-lock, according to th<number of residents. The boxes are moved up and down by electricity. — Piofessor Sohafer believes that, daylight' alone determines bird migration. The summer migrants, he tells us, come north to take advantage of the longer daj's, and go 6ou*h asain to avoid the short and dark ones. They require all their time to get , sufficient, fcod for themselves and their vqra^ious young, and hence the extra day- ; light of the north in summer is an advantage to them. In winter the short days do not allow them to get sufficient. Most ' birds require daylight for feeding. Professor •Srhafer does not credit the old ex- , planntion that migration is due to cold and want of food. Many species leave this country while it is warm, and food still abundiant. ' — "It has been proved by Elster and Geitel that a negatively-charged wire, ex- , posed for a few hours in the air, receives a radio-active deposit similar in character to the quick-changing products of radium. ' Radium is known to be widely distributed , amongst the constituents of the earth's J crust. Moreover, there is evidence that j the emanation from the radium in the earth j escapes into the atmosplere. From these emanations arise Ihe active deposits of j radium in the atmosphere. The radio-active changes in the air and soil account for the ionisation of the air, and important electric and meteorological effects result, the characters of which are at present imperfoctly understood." In this way Mr A. S. Eve introduces a description in the "Ph : losophical Magazine" of his recent experiments to determine the amount of emanation in the atmosphere.— Knowledge. , — Professor Bordas's discovery of the j effect of radium on certain minerals is said , | by a Parh correspondent to outdo the philo- j sopher's stone. The professor noticed that j tubes of glass containing radium acquired j a bright blue hue, appai-ently unalterable | so he tried the effect of radium on some o i ; the hardest stones. He bought corundum I | at 2s a carat and placed it in contact wi+h radium for a little*more than a month. At the end of that time white corundum had j become yellow, like topaz, blue corundum green, as an emerald, and the violet, sapphire blue. When he took the stones to the jeweller from whom he bought them the jeweller unhesitatingly pronounced them to be topazes, emeralds, and sapphire*, worth about £1 16s a carat. The professor then bought a fresh set of corundum stones, two light red, two violet, and two blue. The light red became ruby red, rhe violet sapphire blue, and the blue emerald green The rubj--red corundum- was tested, and pronounced to be a ruby valued at from £20 to f-30 a carat. "Professor Bordas's discovery seems undoubted. If it be com pletely confirmed, what will what we now call precious stones be worth in future? All our ideas of gems must be turned upside down The consequences of such a discovery, though we can imagine some of them, are in the main incalculable.." Professor Bordas points out, however, that his discovery has only a theoretic and not a commercial value. " He has transformed ordinary corundum into valuable gems, which is natural as the mineral basis is the same, but it is great exaggeration to imagjne that the market of precious stones is going to be upset by his discovery. If radium wei-e less rare there might be some fear of a disorganisation, but radium is worth over £7,000.000 per lb. All that is known to exist to-day is two centigrammes, and of that Madame Curie owns half. The professor has but 10 milligrammes; and working with one milligramme of radium it takes over a month to make a topaz from a corundum stone, co that not many topazes could be produced in a year. It is not likely that those who own radium will amuse therasehes making precious stones,

and if they did their work would not have the slightest effect on the market. — The Corporation of Trinity House are at present experimenting with the, S V l '? marine bell signal apparatus, with which they have already equipped the lightships, the Tongue, at the mouth of the Thameß ; the Rov a'" Sovereign,^ in the Jin^ljslj Channel; tKp Outer TXnvsing, of , the Humber, and the East (?6<xhvjn. .'The' system is now in- uso ori over'36o Vessels, Representing an aggregat<? M tbhnage' of-'iiearly' I;5O0,0OO tons. On board ship the submarine" btell equipment is remarkably simple 4 ,' consisting of two tanks fastened against the side of the vessel in the forepeak. Microphone^ are immersed in each, and wires' connect them with an indicator box on the -bridge or in the ciiarthouse, and by means: -of'Jjelephonic receivers tho officer in charge can -instantly locate hij position when' nearing .a' lightvessel or buoy equipped with the bell. Tiiis it placed about 25ft below the surface, and is controlled by ,a code-ringing device in the engine-room or by -the movement of the waves. So accurately, indeed,, does the apparatus work that the bell "sound's can be heard up to a distance of 10 miles.—'Has it evef 'Occurred to you thai the vanilla with j which many a favourite" dish of 5 - ours is flavoured' is made from coal? Will you believe that most of the dyes which have stained the fabrics of your clothes, that the naphtha and benzine which your tailor uses in removing stains, and that even thf sweetest perfumes are all of them derivales of coal? It was once said by a scientist, cleverer and more imaginative than most of his kind, that eoa.l is "buried sunshine " Few definitions, no matter how yainstakingly they have been framed, describe with anything like the simple, forceful directness of this the real nature of the vast black deposits tljat constitute the very life-blood of our industries. Every one knows that coal is of vegetable origin, and that plant-life cannot exist without the siin. Sonio hundreds of thousands of years ago, when this earth was covered with dense forests, the sun began its work of converting the carbonic acid gas 'of the atmosphere ir.to solid carbon, and trees and plants began to store up its energy. Year by year the leaves, twigs, and branches which had flourished under the sun's warmth and light diopped at the foot of each tree, and formed beds of peat after they had accu mulated in sufficient quantities. Layer upon layer of vegetable material piled up, until the pressure on the underlying 1 masses compacted them into what we now term "coal." The internal heat of the earth, then much more intense than now, drove off some of the gases and made the change more complete. Something of the enormous extent of ancient coal-forming iungles may bo conceived when it is said that our present foresto would produce only two or "three inches of eoa.l if they, too, were subjected to a carbonising process. The magicians who have wrought wonders with coal aro the gas-maker apd the chemist. If coal "is burnt in the open air. heat is produced and nothing left but a little ash. Burn it in a closed vessel, however, and marvellous changes occur. In the first place, coal-gas-is produced, and, chemically treated, is supplied to every city home. Furthermore, ammonia is obtained, -important in modtern agriculture because by its means plants can be artificially supplied with the nitrogen they need. ' Then, again, asphalt is produced, much used in road-making, although the gas retort is not the chief source of its supply. Lastly, a black, noisome ooze is collected which goes by the name of "coal-tar." It is this which, at the touch of the modern chemist's wand, is transformed into the most widely different substances imaginable. Every hue of Nature has been extracted from this foul-smelling coaJ-tar, and in addition many beautiful colours utterly unlike anything to be found in Nature have been charmed out of it. To such proportions has the coal-tar industry grown that natural dyes are nowadays rarely employed. Splendid, red 6of all shades, delicate blues, rich greens, exquisite yellows, warm browns, and dead blacks are now all obtained from coal. The dyes thus artificially made are numbered by thousands. Hardly a week passes but the disoovery of a new one is chronicled by scientific journals.— W. B. Kaempffert in the Pail Mall Magazine.