G.— ENGINEERING 133 



widely used and effect a great saving in time and personnel. It would 

 seem that the Drumm battery or some of the other new traction batteries 

 may give a sufficiently long range to the pure-electric independent- 

 running locomotive. In a country like ours, where we have no very large 

 supplies of oil, the pure-electric locomotive is of course to be preferred 

 to the Diesel-electric. For we would rather get our power from our own 

 coal than from imported oil. It would be worth while for the nation to 

 carry out very extensive researches on batteries possessing the required 

 characteristics. One can conceive methods of changing batteries so 

 rapidly that no excessive weight need be carried, and the speed between 

 the stops might be so great that a very satisfactory express service could 

 be run. In this connection we must remember the great advantages that 

 can be gained by using some kind of adjustable speed-torque conversion 

 system between the electric motor and the axles. The performance of 

 a locomotive can be enormously improved by the addition of such a 

 system of transmission. This is of especial importance in a battery- 

 driven locomotive, as it does away with complicated control gear and the 

 necessity for high rates of discharge. Two very great advantages would 

 result from the adoption of such a locomotive : (i) the change over from 

 steam to electricity could be made gradually and without requiring any 

 special equipment of the line ; (2) in times of war the railway system 

 could be kept running. To make our railways dependent on the con- 

 tinuity of overhead lines is to present such a vulnerable feature to the 

 enemy as almost to invite war. 



As soon as the characteristics of the battery-driven locomotive are suffi- 

 ciently good, see what an opening we have in this country for the battery- 

 driven motor-car 1 Instead of thousands of cars burning petrol, costing 

 the nation eighteen millions per annum, and polluting the air of our 

 towns, we would have cars driven by home-generated electricity. Imagine 

 hundreds of battery-charging stations, twenty miles apart along our main 

 roads, at which we could in the course of a few seconds drop our partly 

 discharged battery and take a new one that would carry us for the next 

 three or four stages. The batteries would probably belong to the Central 

 Electricity Board, and would afford a very nice load for the early 

 hours of the morning. I do not say that we see our way to such 

 perfect batteries yet, but they will probably come some day. The best 

 figures at present seem to be about 10 watt-hours per pound of 

 material, but the theoretically possible figures are much better than 

 this. Experiments on very light motors for traction purposes show 

 that it is possible to make motors of about half the weight of those 

 ordinarily used. 



We live in the hope that with all these developments, and with the con- 

 tinual cheapening of the cost of generation, electricity is going still further 

 to simplify our factories, lighten the work of the housewife, and make 

 our cities clean and healthy. 



So far as the work of the engineer is concerned in the building of super- 

 power stations and the equipment of overhead lines and sub-stations, 

 everything has been done in a most praiseworthy manner. The increase 

 of output of some of the power houses feeding the grid is remarkable. 



