SCIENCE NOTES.

Otago Witness, Issue 2667, 26 April 1905, Page 65

SCIENCE NOTES.

—On a ?mal! scale, at least, Mr J. B. Fowler, an American inventor, lias succeeded In perfseting an ordinary telephone jo that yoi caa see the person you are. talking- with at the other end of the line. At the present time the- remarkable exploits of Mr Fowler's invention are confined to his own residence in Portland, Maine, and he ,is still working on details of perfection. Incredulo-ts visitors .are able to see the features of Ihe persons they are talking with •by looking into a lit. l le arrangement just above the telephone mouthpiece, which icoks like the fro at end of a large camera.

iWhen worked out in all its details,

Powler bolie.v-ss his invention will be of the widest possible use. ''When my invention is perfected." he says, "it will be possible for two people, miles apart, to converse over the telephone, and not only -hear each

other distinctly, but to see each other as well. How thac is ±o be done is my , secret. , Since 1878 I have been trying to invent a photophone, and at last I havesucceeded. , Tha most amazing feature of

my invention is its simplicity.

After puzz-

ling ever it for years and years I accidentally stumbled across the solution a few

weeks ago, and at once constructed the experimental photophone service now in use _in my home. It is a complete success, as I will show you, and now that it has been demonstrated that reflections can be conveyed from one "phone to another 30ft or 10ft away, I am at work on a more extended photophone connection, in which the reflections of two persons several miles apart will bo- "visible over the 'phone to each other. Those mirage rays which con. vey the reflection are operative for hundreds of miles. Space is of no more object than it is in the use of the telephone.'* The visible parts of thp telephone in Mr Fowler's house — that is, the receiving and transmitting portions with which the average person is familiar — are very similar to those in an ordinary 'phone. , The only noticeable addition is a camera-like attachment with a magnifying lens in the centre. This lens is about 3in above the telephone mouth-

piece, so that a person talking into the 'phone is looking- intently at the transmitting lens, and getting his reflection into perfect focus. When he has done this he can turn out the light, taking care, however, not to sway or move from his position during the ensuing conversation. If he mo\es the reflection in the transmitting lens beeon:es hazy, or out of focus, and the person at the other end of the line notices it in the receiving- lens into which he is gazing, and on which the image of the person with whom he is talking' is thrown. How this, image is conveyed from one end to the other is a mystery. . Still, as Mr Fowler declares, the secret is based on a problem of the simplest possible kind. —It is the natural fate of human contrivances to become very scoa obsolete, and especially is thi 1 * the case with the aj\oliss ees which every civilised nation employs for the destruction of its enemies. Ships and guns costing millions of money, which at the time of their construction wore the best procurable, are cast aside very often before they have seen any active service at all. We learn one- day that the British army has the finest rifle of any body of troops in the world ; a short time elaji'-es, and the order goes forth that it is to be replaced by something better. Our army is just now in this transition state with regard to its artillery. New guns are to replac-e ihe old ; and if all reports be true, the fresh weapons, charged with an improved form of cordite, will be of remarkable efficiency. For example, an 18pounder gun. with a charge of only l£lb of cordite, will be- able to pepper an enemy with shraprel at a distance of four miles at the rate, of 15 rounds -cor minute. At a distance of two and a-half miles effective aim will be possible, while ar a mile and ahalf most accurate shooting will be secured. Each gun will carry about 100 rounds. / —In view of the ever-increasing demand for whiter fiour, it is interesting to note that a novel application of electricity for this purpc-e has recently been presented to the French Academy of Sciences. The percentage of the wheat used for "best •whites'' has dropped within the "last 30 years, owing to the elimination during grinding of the- glutens (incidentally the most nourishing portion of wheat), from 75 per cent, to 65 per cent., and latterly to 55 tier- eont. Now. according to "Everyday Electricity." electricity has been called in to s.ss-ist the process. M. Lucas, manager of tho wheat markets of Paris, has supplied a san-.nle of flo-jr produced by the ordinary method* and a sample which has been sub"inittpd to the electric current. At ■fii'st Bi«hh wo are a«s-irod, the latter it indisruiably ii biter, flthoagh the smell and

taste are not so agreeable. The air "electrise" with which the flour is treated appears to act especially on the natural oils of the wheat and to whiten whac is ordizarily a somewhat yellow compound. In other words, it is oxydised and slightly turced into acid. The gluten is also whiter and rather harder. A piece of bread made from this flour was submitted to the Academy, and was found to be distinctly whiter but rather more flavourless than aa ordinary sample of bread.

— A novel apparatus has been presented to the department of comparative anatomy of Brown University by the medical friends of the department in Providence and other cities. It is a projection lantern, known as tho epidiascope, made by Carl Zeiss of Jena. The peculiarity of this apparatus is that it is capable of producing representations of opaqu© objects upon a screen directly. It is therefore not necessary, in case of email objects Bin or lOin in diameter, to make lantern slides, or even photographs. If an open watch, for example, is placed upon the carrier of the machine, the whole audience may "see the wheels go round." The natural colours and the texture of the objects are reproduced exactly. Bright-coloured beetles and butterflies appear upon this screen, with no diminution of their brilliant hues, metallio lustre, or soft bloom. Coloured drawings, printed pages of books, small pictures, evm live animals or fishes in a dish of water arc readily projected. Transparent objects, like lantern slides, may also be thrown upon the screen satisfactorily, as in the case of the. common form lantern, for by simply moving a lever the operator can direct tho light through the object instead of upon it. A microscopic attachment furnishes another feature of the apparatus, and microscopic slides can be projected with varying magnifications, depending ttpon the combinations of lenses. The apparatus is the first of its kind — excepting that exhibited in St. Louis — to be installed in America. — Milwaukee Sentinel.

— Plans for a wonderful electrical feature are being worked out by experts for the Lewis and Clark Exposition at Portland, Oregon. A searchlight, casting a beam of light 80in wide, which will pierce the darkness for a distance of 200 miles, will be placed on the crest of Mount Hood, which rises to a height of 11,255 ft above sea-level, and is distant miles from Portland. From the Exposition grounds four snowcapped peaks — Mount Hood, Mount Ranier, Mount St. Helens, and Mount Adams. — can bo seen on any clear day. When the rays from the monster searchlight on Mount Hood are directed upon one of the other peaks it will make the mountain stand out in bold relief, its every cleft and crag visible much more cleaily than in brightest sunlight. It is calculated that the flash on Mount Ranier. which is 100 miles from Mount Hood, could be plainly seen on a clear night from cities on Puget Sound, such as Seattle and Tacoma, and that vessels 120 miles off .the coast could make out plainly the wide beam in the sky. The cost of Installing the monster searchlight on Mount Hood will be 30,000d01, and th*--oferation will entail considerable labour and a great deal of engineering skill. In order to secure sufficient power for the light, a transmission line will have to be built to a. point '-wear Cloud Cap Inn, 6800 ft up the mountain side, and a temporary generating plant installed at this point. The searchlight will be placed on a short tower of wood and iron, erected at the highest point on Mount Hood The lower part of the tower will be used for the apparatus and operators. As -the- temperature on Mount Hood every night is far below the freezing point, arrangements will b© made so that the operators, snugly housed in the bas& of the tower, may operate the transformers and motors without exposing themselves to the cold. In addition to the searchlight effect from the summit, the establishment of the electrical apparatus affords means for ihe general illumination of tho mountain by arc light?. One hundred arc lights, equal in power to those used in street illumination, will be distributed on the side of the mountain facing Portland, so that the whole mountain side will be brillia"tlv illuminated. Besides the use of the searchlight and arc lights, great quantities of red fire will be used to produce another unique effect. When the red powder is burned it will give the peak the appearance of a. mountain wrapped in flames. This latter effect has been produced on several occasions by tho us© of 501b of red fire.

— Talking the other day about his first experiments with the electric light, Mr Edison remarked: "The first eioctrio lights I saw were two arc lamps that were part of a circus side show. Few persons thought then the light would ever be any use commercially. Tt was too bright and too big. The problem that suggested itself to mo was a suitable subdivision of tho light and distribution of it to people's holies, the sa.roe as ga*. After endless experiments I decided to try a simple carbon thread. I sent out, got some cotton thread, carbonised it. ami made the first experiment. That was October 21, 1879. Afte-i tho lamp was lighted and burned into a steady glow I watched it with a fascination I "cannot describe. For more than 40 hours I scarcely moved from my chair, watching that lamp with ever-increasing fascination and elation. After it had burned continuously 45 hours I werfc to bed convinced that the problem was solved." — Red Letter.

— Among the principal radio-active minerals (says the Dublin Penny Journal) may b© mentioned thorite and orsanite. Both of them have been examined by 11. Cuiie. These two minerals are analagous as regards their chemical composition, but they are distinguished from each other by their exterior aspect and the different amounts of thorium which they contain. As to thorite, it is a hydrated silicate of thorium

which contains about 60 per cent, of oxide accompanied by a great number of bodies, among which are oxides of iron, manganese, calcium, uranium, magnesium, and lead, with potassium and sodium compounds and stannic acid. This mineral is obtained principally in the neighbourhood of Brevity, 1 Norway. In the natural state the thorite I is found in the form of amorphous masses, j whose colour varies from chestnut brown to blackish brown. It is found but rarely in the crystallised state ; in this case it occurs in dode-caheral crystals. In general, the thorite which occurs in Norway has ! a resinous lustre and a conchoidal fracture. When reduced to thin plates # . it is trans- , Iveent and sometimes even* transparent. Its density varies from 4.6 to 4.8, and its [ hardness is 4.5. The main characteristics ! which enable it to be distinguished are, in the first place, its colour, thon its density and hardness. Some additional tests are also needed. When heated, it gives off water vapour. On treating with hydrochloric acid it is attacked, and forms a jelly-like mass. Sulphuric acid dissolves it when hot, even after calcination. It is only fused with difficulty by a blow-pipe. When melted in a, borax drop at the end of a platinum wire it gives an orangeyellow mass, which becomes greyish ui)on cooling. A little nitrate of potash added to the melted drop allows the orange tint to remain even after cooling. It is in one of the specimens- found at Brevig that Berzelius discovered thorium in 1828. Mme. Curie examined a. great number of specimens of thorite. The following figures show the radio-activities of these different specimens, taking metallic uranium as unity. Uranium, 1.0 ; thorite- from Lovo, Sweden, 0 58; different thorites, 0.04, 0.13, 0.57, 0.62. These determinations were made with an electrometer method which is very precise. It consists in measuring the current which passe-s a condenser formed of two plates, on the lower of which is placed the test substance. The second mineral, organite, is a variety of thorite. It always accompanies the lattei-, and it is also found at Brevig, Norway. However, its coleur is different. Ifc is either orange-yellow or orange-brown. Its proportion of oxide of thorium varies from 70 to 75 per cent. Its density is 5.4. The distinctive characteristics of the minerals are the same as for thorite. As the rrineral is richer in thorium, it is also more active, and some samples which were found showed a relatively high activity. The result of a certain number of measurements, taking uranium as unity, gives the values 0.87, 068 OS9 and 1.10.