42 6 POPULAR SCIENCE MONTHLY. 



though in Mond gas Parliament sanctioned a novel and rival method 

 of power transmission. While its use for lighting, for electrolytic man- 

 ufactures, etc., steadily advanced, it was in regard to its applications to 

 traction that electricity was most conspicuous. Some schemes of this 

 sort were brought into actual operation, some were definitely decided 

 upon; but more still were mere suggestions, few of which have much 

 chance of being translated into fact. Among the last class must be 

 ranked the host of tube-railways which threaten to invade London. If 

 Parliament were to sanction all those proposed and if (what is not less 

 unlikely) their promoters were to obtain the money for their construc- 

 tion, it seems that in some places the subsoil of the City of London 

 would be transfonned into a solid mass of iron tubes, and it is doubtful 

 whether there would even be room for all in the earth, whatever the 

 ingenuity of drawing-offices may do in plans. This activity on the part 

 of promoters is largely a result of the success of the Central London 

 Eailway, but it is conveniently forgotten that there are other tube rail- 

 ways which cannot point to anything like similar results. In the near 

 future, too, it does not seem improbable that there may be a change in 

 popular sentiment in favor of shallow lines just below the surface, where 

 efficient ventilation will be obtainable; for people are discovering that 

 steam and sulphur are not the only things that make an atmosphere 

 offensive, and they may soon realize that to roll a mass of used-up air 

 forwards and backwards in a narrow tunnel, without ever renewing it, 

 does not constitute ventilation sufficient either for comfort or for health. 

 During the year many towns brought electric traction into operation on 

 their surface tramlines, and after protracted obstruction the authorities 

 of Kew Observatory, who feared that certain magnetic observations car- 

 ried on at that somewhat unsuitable site would be injuriously affected 

 by stray electric currents, agreed to withdraw their opposition to the 

 opening of the first electric tramway seen in London, in consideration of 

 the company which owns the lines contributing £10,000 towards the 

 expenses of moving the instruments. Among proposals which were 

 definitely determined upon may be mentioned the adoption of electrical 

 propulsion for the Mersey Eailway in Liverpool, and for the Metro- 

 politan and District Eailways in London, both to a large extent 

 with the aid of American capital. For the latter, two systems were con- 

 sidered — the Ganz polyphase and the ordinary direct current. The 

 question which should be selected was referred to the Board of Trade for 

 decision, and as soon as that step was taken the matter was practically 

 settled, for few could doubt but that so eminently conservative a body 

 would choose a system which has been well tried in various parts of the 

 world, in preference to one which has scarcely passed the experimental 

 stage, and which, moreover, involves the employment of electricity at 

 a much higher pressure than it is used to. In another case also the 



