A SERIOUS hindrance to the rapid development of public electric supply in Great Britain is the great inequality in the charges made for electricity in many neighbouring districts. In a paper on public supply tariffs by J. A. Sumner read to the Institution of Electrical Engineers on February 28, it is concluded, after a careful study of methods of lowering the costs of distribution, that it is not unreasonable to forecast that electricity will be available within the next few years to all consumers at a rate of 0·5d. per unit. Mr. Sumner begins by comparing the costs per kilowatt of a private supply station with that of a public supply. Statistics for the case when Diesel engines are used for the private supply prove that it is the more expensive. It appears that many undertakings are selling electricity for power purposes at a lower rate than is required to compete with the real costs of running private plant. Hence in some cases the domestic consumer is penalised unfairly. It is pointed out that the distinction between ‘urban’ and ‘rural’ supply is sometimes unnecessary, as in many cases the capital expenditure for dwellings near the mains is much the same in the two cases. The analysis of the statistics proves that the merging of electricity areas into much larger single districts than at present is necessary for the reasonable standardisation of tariffs. It is possible in this way to balance the inevitable deficit of a newly-developed area against the surplus from the older areas. By this means a uniform tariff can be kept throughout each single large administrative district.