1^,6 



NA TURE 



\_Dcc. 9, 1880 



must always be a subject of interest ; and while MM. Covnu 

 and Mascart, and others, have extended our knowledge of the 

 ultra-violet end, Major Abney has opened out to us a new region 

 beyond the red. 3 Lord Rayleigh and others before him have 

 however proved that there must be a limit at the least refrangilile 

 end of the spectrum. Prof. .Stokes, long since, noticed the 

 difference in length between the spectrum of the sun and thai of 

 the electric arc ; and M. Cornu has recently shown by observ.i- 

 tions at elevated stations that the great rapidity of atmospheric 

 absortion must preclude the hope of any great extension of the 

 solar spectrum toward the more refrangible end. 



The striking advances made in electricity during the last few 

 years, and marked by, amongst other things, the inventions of 

 the telephone and the microphone, have been followed by a 

 step not less daring in its conception, nor less successful in its 

 execution ; I allude, of course, to the photophone, the result 

 of the researches of Mr. Graham Bell and Mr. .Sumner Tainter. 

 The principle of this instrument is already known. A powerful 

 beam of light is first thrown upon a flexible mirror, the curvature 

 of which is mrxlified through vibrations set up in it by the 

 'mman voice. The reflected beam is then received by a selenium 

 " cell " forming part of an electric circuit. The intensity of the 

 licht so received, and with it the resistance in the circuit due to 

 the selenium, varies with the varying curvature of the flexible 

 mirror. A large par.abolic mirror is used at the distant station 

 to concentrate the light on the selenium "cell"; and a 

 telephone in the circuit reproduces the variations in the form 

 of sound. 



Mr. Bell has however also shown that rays from the sun, or 

 an electric lamp, when rendered intermittent by any convenient 

 means, will set up in a plate of almost any substance vibrations 

 corresponding to the intcrmittence. The substances as yet tried 

 are : metals of various kinds, wood, india-rubber, ebonite, &c., 

 and among them zinc appears to be one of the best suited for 

 the purpose. This result, wliich is independent of any electric 

 action, is perhaps due to heat rather tlian to light. 



In these, as in many other issues of scientific research, we 

 can hardly fail to be impressed by the almost inexhaustible re- 

 sources which lie ready to hand, if we only knew how to use 

 them, for the inteipretation of nature or for the practical 

 purposes of mankind. 



During the past year Trof. Hughes employed his induction 

 balance for tlie detection of very minute impurities in small 

 masses of gold. Mr. Preece also has shown how slight incre- 

 ments of temperature in fine wires transmitting telephonic 

 currents of electricity will suffice to reproduce sonorous vibra- 

 tions, and even articulate speech, at a distant station by their 

 influence on thin platinum w ires only six inches in lengtli. 



Jlr. Stroh has shown that, at the point of contact of two 

 metals carrying strong electric currents, adhesion takes place, 

 varying with the nature of the surfaces in contact ; and tliat 

 many of the effects at points of contact, previously attributed 

 to induction, may be due to the peculiar action now for the first 

 time brought under notice. 



It is worthy of record that two Atlantic cables have been 

 successfully laid during the present year ; but that the opera- 

 tion has become so much a matter of course, that its occur- 

 rence has attracted little public attention. Two cables, each 

 of more than 500 miles in length, have been laid across the 

 Mediterranean ; and the Cape Colony has been placed in 

 telegraphic communication with this country by a cable of not 

 less than 4400 miles. 



Constant attention is paid in the General Post Office to the 

 introduction of improved methods for the furtherance of the 

 telegraphic communication throughout the country. 



Steady progress has been made in bringing the electric light 

 mto practical use. The illumination of the Albert Dock of the 

 London and St. Katherine's Dock Company, the Liverpool 

 Street Station of the Great Eastern Railway, the St. Enoch's 

 Station of the Glasgow and South-Western Railway, and last, 

 but not least, that of the reading-room of the British Museum, 

 have become accomplished facts ; wliile the City authorities have 

 decided to extend the use of this light over various thorough- 

 fares under their control. Tlie subdivision of the light for 

 domestic purposes is a problem which appears to have found a 

 solution in the incandescent carbon lamp of Mr. Swan. Betides 

 this, Mr. J. H. Gordon has devised, for the same purpose, a 

 very ingenious application of rapid sparks from alternating 

 machines, such as that of De Meritens, to produce incandes- 

 cence in refractory metals. Lamps constructed on this principle 



completely fulfil the c3nditions of subdivision, but sjme diffi- 

 culties of detail still retard their adoption for general use. 

 There is, however, every reason to hope that the experience 

 already gained, and the intelligence at present brought to bear 

 upon it, will before long supply us with more than one form of 

 domestic light. 



The chief question of interest which has occupied the atten- 

 tion of the Iron and Steel Institute has been the adaptation of 

 the "basic " process to the production of steel from pig metal 

 containing a considerable percentage of phosphorus. Hitherto 

 only pure hrematite and spathic ironstones have been used for 

 the production of steel ; but it has now been shown that, by the 

 employment of basic linings and basic slags, the metal is almost 

 completely cleared of its phosphorus, and that steel of good 

 quality may be produced from inferior ore. 



The Conference on Lightning-Conductors, composed of dele- 

 gates from the Royal Institute of British Architects, the Society 

 of Telegraph Engineers, the Physical Society, and the Meteoro- 

 logical Council, is steadily pursuing its labours. A large mass 

 of facts has been accumulated ; several leading questions have 

 been decided ; and it is hoped that, in the course of the coming 

 year, the Report of the Conference will be issued. 



One of the most interesting, and at the same time useful, 

 applications of the dynamo-machines, is that of transmitting 

 mechanical power to spots, or under circumstances, where the 

 ordinary appliances cannot be conveniently used. Their prin- 

 ciple will doubtless by degrees extend itself over a wide range of 

 industry ; especially in localities where water-power is abundant. 

 A very remarkable instance of such adaptations will be found 

 in Dr. Werner Siemens's propulsion of railway carriages in 

 Berlin. 



Our Fellow, Dr. C. \V. Siemens in London, and M. De 

 Meritens in Paris, have demonstrated the use of the high tempera- 

 ture of the electric arc in fusing refractory met.als. The method 

 of operation, while peculiarly convenient for laboratory pur- 

 poses, and for demonstration, promises to be capable of extension, 

 even to the large demands of commerce and manufacture. 



I should not, moreover, omit mention of the very Ijeautiful 

 experiments by Dr. C. W. Siemens on the effect of the electric 

 light on the growth of plants, on the opening of flowers, and 

 on the ripening of fiuit. On this subject we hope to hear more 

 hereafter. He has already commenced a fresh series of experi- 

 ments, r.nd contemplates continuing them during the coming 

 winter. 



I am not sure how far the fact is known to the Fellows of the 

 Royal Society that the Society of Telegraph Engineers has 

 thrown open to the scientific world a remarkable collection of 

 books on electrical science, collected by our late Fellow, Sir 

 Francis Ronalds, and bequeathed by him to that Society. The 

 catalogue, compiled by the collector, is a monument of concen- 

 trated and well-directed labour. 



As regards the Transit of Venus in 1874, the printing of the 

 observations is complete for the two groups of stations in the 

 Sandwich Islands and Egypt, and that for others is in 

 progress. 



Preparations are already being made with a view to the 

 observation of the Transit of Venus in 1882. As a pre- 

 liminary step for this operation, as well as for general purposes, 

 it had been decided that the longitude of the Cape Observatory 

 should be definitively determined by telegraphic connection with 

 Aden, which place is already telegraphically referred to Green- 

 wich ; and, notwilhstanding a temporary interruption on the land 

 line, Capetown-Durban, it may be hoped that the connection 

 will be effected at no distant period. Mr. Gill is prepared 

 to undertake the main share of the work. With the same 

 objects in view, on the urgent representation of the Astronomer- 

 Royal, it has also been determined to connect one of the Austra- 

 lian Observatories with Greenwich, tluough Madras, the longi- 

 tude of which is well known ; and this operation will be very much 

 facilitated by the share which Mr. Todd, Government Astro- 

 nomer and Superintendent of Telegraphs at Adelaide, would be 

 prepared to take in it under the auspices of his Government. 

 The eastern boundary of the Colony having been defined by 

 Imperial Act as the 141st meridian, a wish has been expressed 

 officially for the accurate connection of Adelaide with Greenwich, 

 independently of the Transit of Venus. 



The .\stronomer-Royalhas explained in detail the preparations 

 which he considers necessary, so far at least as this country is 

 concerned, for the effective observation of the transit, and he has 

 introduced several alterations in the plan which he had formerly 



