880 REPORT— 1893. 



sea-level. The conductors from this point are insulated and covered with lead. 

 About three-quarters of a mile in the mine, or 1^ mile from the dynamo, 

 a 9-horse-power series motor is employed to wind ore from a set of sinkers. 

 Further into the mine another quarter of a mile, and down 120 yards at the bottom 

 level, is G.xed another 9-horse-power motor, working a three-throw pump, forcing 

 the water 360 feet in height. 



About midway between these motors there is fixed a dynamotor, which reduces 

 the pressure from 600 to 250 volts for working an electro-locomotive in the lowest 

 day level of the mine, through which runs the water ptimped from the 120-yard3 

 level and the whole of the water used by two hydraulic winding engines. Four 

 horses formerly worked this level. The locomotive runs with twelve waggons, the 

 total weight when loaded being eighteen tons, and does the work of the four 

 horses with the greatest ease. The conductors in the level are phosphor bronze 

 wire, and the current is fed to the locomotive by four contact pulleys. 



The chief difficulty attending the use of water-power is the irregular and some- 

 times intermittent character of the supply, and hence it is necessary to exercise 

 great care in judging the suitability of water for given work. This can be obviated 

 to a large extent by building reservoirs and regulating the output according to the 

 power required ; but when lighting forms an important part of the scheme, 

 secondary batteries maybe used most advantageously. Accumulators act not only 

 as reservoirs, but also as regulators, storing up excess of power, and giving it out 

 when the prime power is insufficient or the turbines ai'e stopped. They are there- 

 fore especially useful on installations for combined power and light when the 

 water-power varies intermittently. And they may be made a source of economy 

 when power is not required both by day and by night, and owing to the want of a 

 suitable reservoir the water runs to waste during the idle period ; then accumula- 

 tors may be used to store the major part of this energy for electric lighting, 

 metallurgical, or even power purposes. 



It will be gathered that the writer is fully aware the small water-power of 

 Great Britain can never show results equivalent to those obtained on the Continent ; 

 yet there is undoubtedly much water-power wasted here that is capable of being 

 profitably utilised. His object is simply to call attention to the improved means 

 of utilising water-power by the turbine dynamos, and to suggest that prompt 

 measures be taken to conserve as much power as possible by a proper attention to 

 the building of dams and reservoirs wherever this may be feasible ; and that such 

 power should be used if convenient, to the exclusion of coal, and, if not so, as an 

 auxiliary power, the steam plant being used as a stand-by as much as possible. 

 This proposal, if properly carried out, would decrease the total consumption of coal 

 to a greater extent than is generally supposed, and would make a number of manu- 

 facturers less dependent upon it than they are to-day, even if it did not appreciably 

 cheapen the cost of power. But in a number of favoured cases there can be no 

 doubt that water-power properly applied would considerably decrease the cost of 

 working, allowing a proportionate gain to both producer and consumer. 



3. On a new Form of Variable Power-gear for Electric Railways and 

 Tramways. By W. Worbt Beaumont, M.Inst. G.E. 



It is a matter of great importance on electrical railways and tramways that the 

 maximum steam-engine power at work in the generating station should be as little 

 above the mean load as possible. 



It is found on electrical railways now at work that there is a great waste of 

 power, and therefore of fuel, in consequence of the large consumption of current in 

 getting the trains into motion by motors attached directly to the axles. On the 

 South London Railway it is found that the power employed electrically in over- 

 coming the inertia of the train is from 25 to 50 and 60 per cent, greater than that 

 required to keep the train going. 



Mr. J. H. Greathead, M.I.O.E., the engineer of this railway, has shown that 

 if this could be avoided from 20 to 30 per cent, of the engine power which must 



