September 4, 1890] 



NATURE 



435 



Oersted, of Ampere, of Sturgem, and of Ohm, and especially 

 the discoveries of volta-electric induction and magneto-electricity 

 by Faraday, paved the way for the development of the electric 

 telegraph as a practical reality by Cooke and Wheatstone in 1837. 

 How remarkable the strides have been in the resources and 

 powers of the telegraphist since that time is demonstrated by a 

 few such facts as these : the first needle-instrument of Cooke and 

 Wheatstone transmitted messages at the rate of four words per 

 minute, requiring five wires for that purpose ; six messages are 

 now conveyed by one wire, at ten times that speed, and news 

 is despatched at the rate of 600 words per minute. Duplex 

 working, which more than doubled the transmitting power of 

 a submarine cable, was soon eclipsed by the application of 

 Edison's quadruplex working, which has in its turn been sur- 

 passed by the multiplex system, whereby six messages may he sent 

 independently, in either direction, on one wire. When last the 

 British Association met in Leeds, submarine telegraphy had 

 but just started into existence ; thirty years later, the accom- 

 plished President of the Mechanical Section informed us, at our 

 meeting at Bath, that 110,000 miles of cable had been laid by 

 British ships, and that a fleet of nearly forty ships was occupied 

 in various oceans in maintaining existing cables and laying new 

 ones. 



The important practical achievements by which most formid- 

 able difficulties have been surmounted, step by step, in the suc- 

 cessive attainment of the marvellous results of our day, have 

 exerted an influence upon the advancement, not merely of 

 electrical science, but also of science generally and of its applica- 

 tions, fully equal to that which they have exercised upon the 

 development of commerce and of the intercourse between the 

 nations of the earth. 



Thus, the laying of the earliest submarine cables, between 

 1851 and 1855, led Sir W. Thomson, in conference with Sir 

 George Stokes, to work out the theory of signalling in such 

 cables, by utilizing the mathematical results arrived at by 

 Fourier in his investigation of the propagation of heat-waves. 

 The failure of the first Atlantic cable led to the survey of the 

 bottom of the Atlantic, which was the forerunner of deep-sea 

 explorations, culminating in the work of the Challenger Ex- 

 pedition, and opening up new treasures of knowledge scarcely 

 dreamt of when last the British Association met at Leeds. To 

 the difficulties connected with the early attempts at submarine 

 telegraphy, and the determination with which Thomson drove 

 home the lessons learned, we owe the systematic investigations 

 into the causes of the variations in resistance of copper-conduc- 

 tors, and the consequent improvements in the metallurgy of 

 copper, which led to the realization of the high standard of 

 purity of metal essential for the efficient working of telegraphic 

 systems, and also to the extensive utilization of electricity in the 

 production of pure copper. The rare combination of origin- 

 ality in powers of research and perspicuity in mathematical 

 reasoning, with inventive and constructive genius, for which 

 Thomson has so long b«en pre-eminent, has placed at 

 the disposal of the investigator of electric science, and of 

 the practical electrician, instruments of measurement and record 

 which have been of incalculable value, and which owe their 

 origin to the theoretical conclusions arrived at by him in his re- 

 searches into the conditions to be fulfilled for the attainment of 

 practical success in the construction and employment of submarine 

 cables. The mirror galvanometer, the quadrant electrometer, the 

 syphon-recorder, and the divided-ring electrometer, are illustra- 

 tions of the valuable outcome of Thomson's labours ; the combi- 

 nation of the last-named instrument with sliding resistance coils 

 has rendered possible the accurate subdivision of a potential 

 difference into lo,ooo equal parts. The general use of condensers 

 in connection with cable signalling, due to Varley's application 

 of them for signalling through submerged cables with induced 

 short waves, was instrumental in establishing the fact that all 

 electro-static phenomena are simply the result of starting an 

 electric current of known short duration round a closed circuit. 

 The practical application of the Wheatstone Bridge led to 

 numerous important mathematical investigations, and induced 

 Clerk Maxwell to devise a new mode of applying determinants 

 to the solution of the complicated electrical problems connected 

 with networks of conductors. The necessity for the universal 

 recognition of an electrical unit of resistance led to the establish- 

 ment, in i860, of the Electrical Standards Committee of the 

 British Association, whose long succession of important annual 

 reports was instrumental in most important developments of 

 theoretical electricity, and, indeed, served to open up the whole 



science of electrical measurement. Matthiessen's important 

 investigations of the electrical behaviour of metals and their 

 alloys, and the preparation and properties of pure iron, were the 

 outcome of the commercial demand for a practically useful 

 standard of electrical resistance ; while Latimer Clark's practical 

 standard of electromotive force, the mercurous sulphate cell, 

 became invaluable to the worker in pure electrical research. 

 The unit of resistance established by the British Association 

 Committee received, in 1866, most important scientific applica- 

 tion at the hands of Joule, who, by measuring the rate of deve- 

 lopment of heat in a wire of known resistance by the passage of 

 a known current, obtained a new value of the mechanical 

 equivalent of heat. This value differed by about i'3 percent, 

 from the most accurate results arrived at by his experiments on 

 mechanical friction, a difference which eventually proved to be 

 exactly the error in the British Association unit of resistance ; so 

 that the true value of the unit of resistance, or Ohm, was deter- 

 mined by Joule fifteen years before this result was achieved by 

 electricians. Clerk Maxwell's remarkable electro-magnetic 

 theory of light was put to the test, through the aid of the British 

 Association unit of resistance, by Thomson, in determining the ratio 

 of the electro-magnetic unit to the electro-static unit of quantity. 

 Many other most interesting illustrations might be given of the 

 invaluable aid afforded to purely scientific research by the practi- 

 cal results of the development of electrical science, and of the 

 constant co-operation between the science student and the prac- 

 tical worker. No one could, more fitly than the late Sir William 

 Siemens, have maintained, as he did in his admirable address 

 at our meeting in Southampton in 1882, that we owe most of the 

 rapid progress of recent times to the man of science who partly 

 devotes his energies to the solution of practical problems, and to 

 the practitioner who finds relaxation in the prosecution of purely 

 scientific inquiries. Most assuredly both these classes of the 

 world's benefactors may with equal right lay claim to rank the 

 name of Siemens among those whom they count most illustrious ! 

 In that highly interesting and valuable address delivered 

 little more than a year before his sudden untimely removal from 

 among us, the numerous important subjects discussed by him 

 included not a few which he had made peculiarly his own in the 

 wide range embraced by his .enviable power of combining scien- 

 tific research with practical work. Prominent among these were 

 the applications of electric energy to lighting and heating 

 purposes, and to the transmission of power, to the future 

 development of which his personal labours very greatly con- 

 tributed. 



Siemens referred to the passing of the first Electric Lighting 

 Bill, in the year of his presidency, as being designed to facilitate 

 the establishment of electric installations in towns ; but the 

 anxiety of the Government of that day to protect the interests of 

 the public through local authorities, led to the assignment of 

 such power to these over the property of lighting companies, 

 that the utilization of electric lighting was actually delayed for a 

 time by those legislative measures. There can now be no doubt, 

 however, that this delay has really been in the interests of 

 intending suppliers and of users of the electric light, as having 

 afforded time for the further development of practical details, 

 connected with generation and distribution, which was vital to 

 the attainment of a fair measure of initial success. The subse- 

 quent important modification of legislation on the subject of 

 electric lighting, together with the practical realization of com- 

 paratively economical methods of distribution, the establishment 

 of fairly equitable arrangements between the public and the 

 lighting companies, and the apportionment, so far as the metro- 

 polis is concerned, of distinct areas of operation to different 

 competing companies, have combined to place electric lighting 

 in this country at length upon some approach to a really sound 

 footing, and to give the required impetus to its extensive deve- 

 lopment. Nine companies either are now, or will very shortly 

 be, actually at work supplying, from central stations, districts of 

 London comprising almost the entire western and north-western 

 portions of the metropolis. As regards other parts of England, 

 there are already twenty-seven lighting stations actually at work 

 in different towns, besides others in course of establishment, and 

 many more projected. The town of Leeds has not failed to give 

 serious attention to the subject of utilizing the electric light, and, 

 although no general scheme has yet been adopted, the electricians 

 who now visit this town will rejoice to see many of its public 

 buildings provided with efficient electric illumination. 



While the prediction made by Siemens, eight years ago, that 

 electric lighting must take lis place with us as a public illuminant, 



NO. 1088, VOL. 42] 



