SCIENCE NOTES.

Otago Witness, Issue 2664, 5 April 1905, Page 68

SCIENCE NOTES.

—An invention that will increase the ~~ipeed of ships by "pneumatic lubrication" pi the water through which the ships pass -is claimed by the Rome Tribuna to have &een by Dr Carlo Del Lungo, {Professor of Physics at the University of Oenca. Describing the invention, this Jaaper says: — "The means which are at our (disposal for the purpose of increasing the speed of ships He either in augmentation of the power of the propelling machinery lor in diminishing the resistance which the ship encounters in the water. Up to the (present it has been sought to diminish ibis resistance by modifying the shape of tli© 5x at, so that the vessel should commmuni- . cate as little movement as possible to the surrounding wafer. Th€> invention of Professor Del Lungo, however, represents an (entirely new departure. This invention does not consist in modifying the ?hape of the vessel, but in altering the physical ccn ? dition of the water which surrounds the ship — that is, in dinrnishing the density of the water. • The modification of tho density is obtained by pumping into the. surrounding water a quantity of air, in *Jms way creating a stratum of water around the vessel which is similar to foam. This fctratum produces an effect analogous to that of fat or oil in the running parts of fc. machine. This explains the name given t>y Professor Lei Lungo to his invention, the pneumatic lubrication of the huils of .vessels. After a series of experiments raade at Livorne, which were entirely successful, Professor Del Lungo ie now conducting others on a larger scale at Livers>col." — Radium is employed in therapeutics tor destroying by its rays or emanation the mipiobes of tuberculosis in diseased lungs, •nd other purposes. Its use is likely to flbe spread, and Mr Hugo Liebar has been studying the best mode of applying it. In k paper to the Society to; Experimental {Biology and Medicine, New York, he has described a method! which is effective and simple. He prefers to use the Radium salt— for exa;nple, broaide, emitpg the rays in very thin layers, or what be calls "radium boatings." To prepare the coatings the radium salt ie dissolved to. alcohol, and a celluloid rod is dipped 1 bnto it, then withdrawn. The alcohol 'evaporates and leaves a thin layer of the salt upon the rod, which can be fixed (the Oiondon Globe explains) by dippinig the rod gnto collodion solution, quickly withdrawing it, and letting the collodion dry. Ani4me dye added to the solution of salt or Jfche collodion shows the extent of the coating. The collodion is permeable by the -ways and emanation of the salt, which are feapabje of producing- bright scintillations Ton a screen of zinc sulphide and other feffects. Such coatings can be applied to jpraotically all parts of the body, and instruments can be coated in the same way. iFor application (he rod may be enclosed in a tube of glass or aluminium. Tubes fcoated internally with the radium salt in fchis way can be used in cases of tuberculosis.

— Professor Constant! .Ie Gregory, of ■Naples, has invented a new chemical process for the preservation of flowers and foliage. When the professor submitted the results of his first experiment to the Nea.politan Institute for the Advancement of Science some weeks ago, the association, after carefully examining them, requested the of some plants which they described, and which, in their opinion, presented the greatest difficulties owing to their Jpeouliar nature. The professor completed the trial set befora him, and he has presot ted son-e splendid examples of begonia find orchid leaves which have a remarknHe jnatural appearance. In recognition of this Irrk he ha? beea awarded the silver modal Qf the institute. The professor is now en-

ga<&ed upon th^ -extension of his inspection to fungi, and' in. the event of his achieving success he will be presented with the society's gold medal. — The recent disastrous accident in the Midlands, resulting from fog-obscured signals, once again emphasises the necessity for some fog-signalling apparatus that can be operated from the signal cabin. From the drawinigS3 and particulars of the Wynford Brierley system, it would certainly appear that the- railway companies have a simple and practical invention within their reach. The apparatus, which for some little time has been under actual trial on the Great Northern railway, broadly consists of twro portions, one part of tho apparatus being attached to the engine and the other being fixed at the side of the track. The engine portion of the apparatus comprises a trigger {or triggers) hanging downwards from a box bolted to the engine frame and connected by direct mechanism to a bell in the cab. The apparatus on the track practically consists of a lever or stud, which, being connected with the semaphore, is automatically placed in the path of the engine trigger whenever the signal is at "danger." Coutact between the stud and trigger rings the bell on the engine. It 19 a welPknown fact that many signalling inventions dependent on striking level's or triggers attached to the engine hfive failed from their inability to withstand the repeated shock on impact. In tho sy&tem under notice the invantoi" gets over this difficulty by providing the trigger with a d</üble-coil sparing (coils in reversed order), which absorbs the force of a blow in either direction. By the employment of two .triggers and a modification of the- track apparatus, "all light" as well as "danger" sigrals can be transmitted to the engine driver. — London Sun.

— The marvels of wireless telegraphy were made plain to a crowded audience at the Leeds Theatre Royal on Sunday, January 22, by Mr Richard Kerr, whose skill in embodying dry scientific truths in popular and sometimes amusing form has en several previous occasions been appreciated by the audiences at the Sunday Lectuie Society's weekly gatherings. Mr Kentraced the history of the development ofwireless telegraphy from the time of James Bowman Lindsay, a prison schoolmaster of Dundee, who sent messages across the River Tay, using the water as a conductor ; through Faraday's discoveries as to the "magnetic field," to Sir William Preece's system of induction by parallel wires. This latter system was used in sending messages across the Bristol Channel, the message sent along a wire on one side of the Channel beingl received at the end of a parallel wire on the other side. Marconi's system was really the discovery of Dr Hertz, and many other systems, suoh as the LodgeMuirhead and the Dr Forest systems, were also modelled on Dr Hertz's suggestions. The difference between Hertz's method and otlers was that Hertz used ethereal waves instead of air waves, a difference illustrated by thunder and lightning — the lightning, which was transmitted by ethereal waves* being perceived almost instantaneously, while tho thunder, which was transmitted by air waves, was much slower in travelling. An electric spark was sent into the air, and the vibrations spreading out in all directions were taken up by a coherer, and it was this coherer which was Marconi's secret. It was a small glass tube filled with nickel filings. These lay in loose disorder till the current came, and then instantly ihey were marshalled into straight lines, and transmitted the vibration. The lecture was illustrated by numerous experiments, including the sending of wireless messagies, and the lecturer pointed out that these messages could only be "tapped" when the receiving instrument was tuned exactly to the pitch of the transmitting instrument . — Le eds Mercurj r .

— "London Electric Railways" formed the subject of a paper read afc the Society

of Arts on January 25 by the Hon. Robert P. Porter. Lord George Hamilton, M.1., who presided, said it was clear that, although there might be no difficulty in largely increasing mechanical means of locomotion in Greater London, yet, as regarded Inner London, it was almost impossible, under existing conditions, largely to increase surface locomotion. They rrust have recourse to underground railroads. Mr Porter, who was introduced as a statistician who had drawn up many tables for the United States Government, and had made a special study of electric railways in Chicago, New York, and elsewhere, said London was essentially a railway, not a tramway, city. There were 531 railway stations, and, with the opening up of the new tubes, this number would be increased to upwards of 600. The length of the trunk, local, local joint, and tubular lines (including those soon to bo opened) in Greater London exceeded 630 miles, thi3 giving a station to every mile of line. Judging from what was now known of the electrical railways in operation, the new tubular- railways would pay. Now and then they heard a sensational story that the tubes had caused cracks in some important building. As a rule, these alarms had proved both foolish and false. One of the more recent had been with regard to St. Paul's Cathedral, but the cracks in St. Paul's were on investigation shown to have been caused as far bade as 1835 by the construction of a deep drain, and, though it was true that the old cracks had been slightly re-opened, the construction of tubular railways, according to the best authorities, could not bo blamed in the matter. He was in no sense an advocate of underground electrical railways as the only system of transportation for Londo l. Street vehicles, surface '•ailways or tramways, overhead railways, and other methods had their place in the solution of the traffic problems of such a city as London. The important thing was to get these all to work in harmony. The unification of the several facilities by some common ownership or consolidation of maragement must be precedent to any really satisfactory or lasting solution of the problem.

— Under the heading "Surveying Made Easy," the followinigi appears in the London Daily Telegraph of February 9: — What is the teletopometer? Professor Cerebotani, its inventor, describes it as "a geodetic universal instrument, adopted for both tracing and sttrveying, even where unapproachable points are concerned, from a single position, without the use of the socalled lath or any substitute, and without any calculation." It is claimed that the instrument has practically solved the difficult question of how to survey distances without making measurements. The operator can read off directly:. (1) The distance of any object; (2) its height above or depth below the horizon of the view point ; and (3) the relative lines of projection. The invention can be adapted for ascertaining the distance of a moving object suoh as a ship, and can be used on the ship itself for determining the distance of another vessel. Incidentally, therefore, it is a range-finder of the titmost value. By the desire of the Admiralty, Professor Cerebotani has carried out a series of experiments with his geodttical instruments, and yesterday, at De Keyser's Hotel, he explained the ; r working to a number of interested visitors. The room was filled with a bewildering array of electrical appliances, for the professor is also the inventor of a number of remarkable improvements in telegraphy, some of which are already in operation on the Continent. For instance, he traced, by means of one instrument, a lady's profile on a sheet of paper, and through the agency of an electric current transmitted in the ordinary way a second instrument at the- other end of ihe apartment simultaneously retraced the outline on a slightly smaller scale. An exact facsimile of the professor's handwriting was produced in the same way. and ho stated that similar "messages" had passed between Berlin and Munich. The same _ results, he claimed, could' be secured by wireless telegraphy. Anyone who can read can wort the apparatus, and it is suggested that it renders it possible for, say, two business men in London and Liverpool to exchange telegrams in their own hand-writing without leaving their offices, and without the intervention of the skilled telegraphist.' Certainly we are still very far from finality in electrical science. Future military engineers, surveying from a balloon an enemy's position, may be able, instantaneously, to transmit a plan of it to their commanding officer some miles away. Professor Cerebotani's invention certainly brings such a possibility nearer.