G.— ENGINEERING. 157 



to 1889. Great Britain may be said to have been the pioneer of the 

 public supply of electricity. The first legislation actually dates from 

 1882, but effectively only from 1888. An electrical supply industry has 

 grown up in Great Britain by authorised undertakers (excluding railways 

 and private plants), in which alone over £200,000,000 has been expended 

 within the short period of thirty-seven years. In the earlier years distribu- 

 tion was confined to low-pressure direct current, with its necessarilv 

 restricted economic radius of supply, and to single-phase distribution at 

 higher pressures for series arc lighting, applied in some districts to what 

 was known as the ' house-to-house ' system at pressures of 2,000 volts, 

 and reduced by house transformers to the required service pressure. 



It is interesting to note that at the present day, owing to the increasing 

 difficulties of meeting the growing density of loads due to domestic require- 

 ments and the relatively high cost of L.T. distribution, there is a revival 

 of the ' house-to-house ' system where there are large blocks of buildings 

 to be supplied. To such blocks of premises H.T. mains can be laid and 

 transformers can be installed locally in order to reduce the street pressure 

 to the low pressure required by consumers in the building itself. 



The whole trend of development in this country was then towards 

 the adoption of small local government areas as the areas of electricitv 

 supply, fostered largely by the technical restrictions brought about by 

 the imperfect systems then available. The scientific world was divided 

 into two camps — one favouring direct current, which has the advantage of 

 using accumulators or storage batteries, and the other declaring in favour 

 of alternating current. At that time only carbon-filament lamps were 

 available, the single-phase alternating motor had not been perfected, and 

 multi-phase currents were commercially unknown. Electricity was 

 supplied mainly for lighting purposes, with a consequent low load factor. 

 Hence very numerous independent systems of small size grew up, with the 

 result that numerous private generating stations were installed in local 

 factories and the larger workshops. 



Individual development rather than collective effort was encouraged, 

 and was, indeed, probably the only way at that time along which progress 

 could have been made. The whole art of electricity generation and supply 

 was also undergoing rapid development, and was the subject of numerous 

 experiments by many designers, some of whom adopted 100 cycles for 

 their alternating-current systems, others 93, 90, 87.5, 85, 83.5, 80, down 

 to 25 or 16 1 cycles, so that a chaotic condition followed, made worse by 

 a want of agreement between the engineers engaged on the work as to 

 the most effective pressures of supply. 



Distribution systems were gradually evolved from a simple 2-wire 

 system, which, due to the influence of Hopkinson, became a 3-wire system, 

 greatly reducing the weight of conductor required for any given amount 

 of energy distributed and also extending the economic radius of supply. 



There were two instances of 5-wire distribution, in Manchester and 

 St. Pancras, but these proved to be cumbersome and costly and were 

 eventually changed back to the 3-wire systems. 



Among one's earliest recollections is the change-over in Kensington, 

 under that veteran Colonel Crompton, from 100 to 200 volts and from 

 a 2-wire to a 3-wire system ; and again under the late Prof. H. Kobinson, 



