NATURE 



[November 3, 1! 



be surmounted well up in the air with one or a cluster of fine 

 points, all the conditions that determine a charge of atmospheric 

 electricity and a flash of lightning are dissipated silently away 

 and no terrible discharge is possible. A mischievous and base- 

 less delusion is prevalent that protectors actually attract light- 

 ning and may be sources of danger. Kvery exposed building 

 should be fitted, but a well-protected dwelling-house is the 

 exception not the rule. Even when protectors are fixed apathy 

 leads to their imperfect maintenance. Their failure to act is 

 always traceable ;o the neglect of some simple rule. Careless- 

 ness is the direst disease we suffer from. Telegraph and 

 telephone wires which spread all over our towns and country 

 are very much exposed to the influence of atmospheric electrical 

 eftecls. Every instrument is now protected. Every telegraph 

 pole has a lightning conductor. Accidents are rare, and the 

 system itself is a public safeguard. In some countries like 

 California and South Africa thunder-storms are very frequent 

 and very severe, but their eflfects have been tamed. 



Tei.ec.rai'HY. 

 In 1S37 Cooke and Wheatstone showed how electricity could 

 be practically used to facilitate intercommunication of ideas 

 between town and town and between country and country. 

 The first line was constructed in July of that year upon the 

 incline connecting Camden Town and Euston Grove Station, 

 the resident engineer being Sir Charles Fox, father of the 

 senior Vice-President. Five copper wires were embedded in 

 wood of a truncated pyramidal section and buried in the 

 ground. The instrument used possessed five needles or 

 indicators to form the alphabet. A portion of this original 

 line was recently recovered in situ. 



The pioneer line of 1837, I J miles long, has, during a period 

 of sixty years, grown into a gigantic world-embracing .system. 

 The extent of the present system of British telegraphs is shown 

 by the following table : — 



Miles of wire. 

 (General Post Oflice and its Licensees .. 435,000 



Railway companies ... ... ... ... 105,000 



India and Colonies ... ... ... ... 387,966 



Submarine cables ... .. ... ... 183,400 



Total ... ... .. 1,111,366 



The speed of signalling and the capacity of working have been 

 increased sixfold, and wires can now be worked faster than 

 messages can be handled by the clerical stafT. 



The form of submarine cable and the nature of the materials 

 used in its construction have varied but very little since the first 

 cable was laid in 1851. The recent invasion of our channels and 

 seas by the Limnoria terebrans, a mischievous little crustacean 

 which bores through the gutta-percha insulating covering, and 

 exposes the copper conductor to the sea-water, leading to its 

 certain destruction, has led to the use of a .serving of brass tape 

 as a defence. It has proved most effective. 



No one has done more than Lord Kelvin to improve the work- 

 ing of submarine cables. His recording apparatus is almost 

 universally employed on long cables. By the duplex method of 

 transmission the capacity of cables has been practically doubled, 

 and this has been still further improved by applying to cables 

 the system of automatic working, which is such a distinguishing 

 feature of our Post Oflice system. The number of electrical im- 

 pulses which can be sent through any cable per minute is 

 dependent upon its form, and is subject to simple and ex.aci 

 laws, but it varies with the quality and purity of the materials 

 used. There is no difiiculty in maintaining the purity of copper. 

 Indeed, copper is frequently supplied purer than the standard of 

 purity adopted in this country — known as Matthiessen's standard. 

 The purity of gutta-percha is, however, questionable. The 

 supply of this dielectric has dwindled ; it has failed to meet the 

 demand ; its cultivation has been neglected. The result is a 

 dearth of the commodity, a great increase in price, and its 

 adulteration by spurious gums. India-rubber, its sole com- 

 petitor for cables, is being absorbed for waterproof garments 

 and pneumatic tyres, but for underground purposes paper is 

 being used to an enormous extent. Paper has the merit, when 

 kept dry, not only of being an admirable insulator, but of being 

 very durable. There is paper in existence in our libraries over 

 1000 years old. The difiiculty is to keep it dry. This is one 

 of the problems the engineer delights to consider. He has been 

 most successful in obtaining a solution. The lead-covered paper 

 cables, which are being laid in the streets of all our great cities, 



NO. I 5 14, VOL. 59] 



are admirable. I am laying one of seventy-six wires for the 

 Post Office telegraphs between London and Birmingham, and 

 the Cable Companies are contemplating leading their long cables 

 from Cornwall up to London, so as to be free from the weather 

 troubles of this svet and stormy island. 



It is impossible to forecast the future of telegraphy. New in- 

 struments and new processes are constantly being patented, but 

 few of them secure adoption, for they rarely meet a pressing 

 need or improve our existing practice. The writing telegraph 

 originating with our late member of Council, E. \. Cowper, 

 which reproduced actual handwriting, much improved by Elisha 

 Gray, and called the " Telautograph," is steadily working its 

 way into practical form, and electrical type-writing machines of 

 simple and economical form are gradually replacing the ABC 

 visual indicator. The introduction of the telephone is revolu- 

 tionising the mode of transacting business. There seems to be 

 a distinct want of some instrument to record the fleeting words 

 and figures of bargains and orders transmitted by telephone. 

 Hence a supplement to that marvellous machine is needed. The 

 telautograph and electrical type-writer will fill this want. 

 Visions of dispensing with wires altogether have been fostered 

 by the popularity of .Marconi's "wireless telegraphy"; but 

 wireless telegraphy is as old as telegraphy itself, and a practical 

 system of my own is now in actual use by the Post Office and 

 the War Department. 



Telephony. 



I was sent, in 1877, together with Sir Henry Fischer, to 

 investigate the telegraph system of the American continent, and 

 especially to inquire into the accuracy of the incredible report 

 that a young Scotchman named Bell had succeeded in trans- 

 mitting the human voice along wires to great distances by 

 electricity. I returned from the States with the first pair of 

 practical instruments th.at reached this country. They differed 

 but little from the instrument that is used to-day to receive the 

 sounds. The receiver, the part of the telephone that converts 

 the energy of electric currents into sounds that reproduce speech, 

 sprang nearly perfect in all its beauty and startling effect, from 

 the hands of Graham Bell. But the transmitting portion, that 

 part which transforms the energy of the human voice into electric 

 currents, has constantly been improved since Edison and Hughes 

 showed us how to use the varying resistance of carbon in a loose 

 condition, subject to change of pressure and of motion under the 

 influence of sonorous vibrations. The third portion, the circuit, 

 is that to the improvement of which i have devoted my special 

 attention. Speech is now practically possible between any two 

 post-oflices in the United Kingdom. We can also speak between 

 many important towns in England and in Prance. It is theoret- 

 ically possible to talk with every capital in Europe, and we are 

 now considering the submersion of special telephone cables to 

 Belgium, Holland, and Germany. 



Railways. 

 The employment of electricity in the working of railways has 

 not only been highly beneficent in the security of human life, 

 but it has vastly increased the capacity of a road to carry trains. 

 The underground traflic of the metropolis is conducted with 

 marvellous regularity and security, though the trains are burrow- 

 ing about in darkness and following each other with such short 

 intervals of time, that the limit of the line for the number of 

 trains has been reached. Electric traction is going to extend 

 this limit by increasing the acceleration at starting and improv- 

 ing the speed of running. It w ill also reduce the cost of work- 

 ing per train-mile, so that the advent of electricity as a moving 

 agency is certain to prove highly economical. What it will do 

 as a remover of bad smells and foul air and for personal comfort 

 cannot be estimated. Time alone will enable us to assess the 

 intrinsic value of public satisfaction acquired by the change. 



DOMESIIC .\l'PI lANCES. 



The introduction of electricity into our houses has added 

 materially to the comfort and luxury of home. If we were 

 living in the days of ancient Greece, the presiding domestic 

 deity would have been Elntra. The old bellhanger has been 

 rung out by the new goddess. Electra has entered our hall- 

 door, and attracts the attention of our domestics, not by a 

 gamut of ill-toned and irregularly-excited bells, but by neat 

 indicators and one uniform sound. The timid visitor fears no 

 more that he has expressed rage or impatience by his inex- 

 perience of the mechanical pull required at the front door. The 

 domestic telephone is coming in as an adjunct to the bell. Its 



