G.— ENCIINEERING. 177 



This may be expressed in the following terms when applied to various 



classes of consumer : — 



A.C. energy transmitted in bulk to large From 0.5(1 to Q.25d. per unit, 



consumers, such as railways and large according to increasing load 



industries factor. 

 A.C. energy distributed locally for 



general domestic purposes, including 



lighting . . . . . . . . About O.Sd. per unit. 



Lighting only . . . . . . . . About 2d. per unit. 



Small power supplies . . . . . . About l.25d. per unit. 



As was previously mentioned, energy in bulk and supplied after simple 

 transformation directly from the high-pressure transmission system can 

 then be sold for an average of 0.4 penny. It is the capital expenditure there- 

 after on local distribution systems and their operating costs which raise 

 the price to the local consumer. In the figures referred to it will be noted 

 that the average cost of low-tension energy after distribution is 2J times 

 the average cost of energy requiring only high-pressure transmission lines. 

 And when one speaks of an average cost of xn^^is of a penny, even after this 

 cost of local distribution is included, it must be remembered that local 

 costs of distribution differ widely at the present time, due mainly to the 

 differing densities of load and load factor and number of consumers served 

 per unit length of main laid. Therefore, although it will be possible 

 hereafter to supply electricity for lighting purposes at an average cost of 

 2d., it is certain that sparser districts will have to pay more owing to the 

 incidence of the capital expended on local distribution, unless a much 

 greater freedom is allowed in the use of overhead lines. One cannot 

 readily understand the great objection raised to the use of such lines if 

 they be properly designed and erected. They are far less obtrusive than 

 the ordinary telephone and telegraph lines which are now so ubiquitous. 

 Light steel taper poles painted to suit their environment are barely notice- 

 able, and in many places bracket attachments can be made to buildings. 

 Without entering into too much detail, it is enough to say that local distribu- 

 tion systems in villages can be installed at a quite small expenditure, and 

 local communities must assist in this matter if they desire to obtain the 

 benefit of a cheap electrical service at an early date. 



What prospect is there of electricity helping what is, after all, our 

 greatest industrj'- — agriculture ? For it umst not be forgotten that half 

 of the area of the country is farm- laud, and that there are nearly 500,000 

 farms in Great Britain. For several years past it has been a matter of 

 great interest to preside over a Committee appointed by the Minister of 

 Agriculture and Fisheries, the purpose of the Committee being to investi- 

 gate the application of electrical discharge to the growth and yield of 

 crops. Under the patient and skilled investigation of Prof. V. H. Black- 

 man, assisted by that great authority Sir E. J. Russell, experimental 

 work has now been conducted at Rothamsted and at Lincluden for several 

 years, with variable but on the whole definitely encouraging results. 



For the time being work is concentrated on scientific pot-culture and 

 small-plot observations, but it is hoped soon to resume field experiments 

 on a wider and practical scale. While the future may reveal a way by 

 which electricity can be used directly to stimulate growth and improve 



1926 N 



