1 chief at £500; | | | 2 assistants at £200 each; | | | 4 clerks at £80 each | · · | | | | | 1 chief at £500; | | | 1 assistant at £200; | | | 4 clerks at £80 each | 1,020 0 0 | | +-----------------+ 1,995 0 0 | _Maintenance of Plant_— | | | Motive power and dynamos: | | | 10 per cent. on £18,010 | · · | | 10 per cent. on £13,400 | 1,340 0 0 | | Buildings and fittings: | | | 5 per cent. on £11,000 | · · | | 5 per cent. on £8,000 | 400 0 0 | | Transformers: | | | 10 per cent. on £7,500 | · · | | Accumulators: | | | 15 per cent. on £9,600 | 1,440 0 0 | | Mains: | | | 7½ per cent. on £20,430 | · · | | 2½ per cent. on £26,262 | 656 10 0 | | Regulating gear: | | | 10 per cent. on £500 | · · | | 10 per cent. on £2,500 | 250 0 0 | | +-----------------+ 4,086 10 0 | + +-----------------+ | | 8,598 10 0 | + +-----------------+ 2,100 units × 365 days | | | = 766,500 units. | | | Cost per unit | · · | 2·7_d._ | -------------------------------+-----------------+-----------------+ With the exception of the amount allowed for depreciation of the accumulators, which time alone can show to be correct, the expenses may be said to be over rather than under-estimated; the 15 per cent. depreciation given in Table IV. is under what has hitherto been found necessary to allow for the renewal of the plates of a secondary battery.