In restoring the ovens heavy expense is incurred. The antiquated and wasteful bee-hive oven can be renovated at a trifling price, but the modern by-products recovery oven entails far heavier expense before the resumption of operations. The charge varies according to the care which has been bestowed upon its maintenance, but, if this has not been conducted along careful lines it may easily incur an expenditure ranging up to 15 per cent. of the original cost of the plant. This charge, unless defrayed out of the renewals account, must be carried to capital. In view of this circumstance the general practice has been to install the by-product system to take care of the constant load--the output of coke to the degree below which it cannot fall even in periods of extreme depression--and to utilize the obsolete bee-hive oven to take care of the fluctuations from the irreducible minimum to the maximum. This margin being extremely wide naturally, the bee-hive still holds sway, and so continues its wasteful reign unchecked. To extend their field of activity and to provide an outlet for the products of their brains the Germans made an astute commercial move. They expressed their readiness to equip the British coking plants with their modern by-product recovery system on condition that they were to be at liberty to acquire the liquid residual--benzol. The suggestion found certain favour in British eyes. The benzol was a drug on the home market, so its shipment to Germany was regarded as the solution of a perplexing problem. In this manner Germany secured the necessary raw materials from the British scrap-heap to feed her dye industry and to pile up her reserves of high explosives against the day when the gauntlet should be thrown down. There is a tendency in certain quarters to assail the cunning competitor, but are we rather not to blame for our own extreme shortsightedness, lack of initiative, and indolence? The coking-ovens, however, only absorb a portion of our total output of coal, the annual average of which may be set down at approximately 260,000,000 tons. Subtracting 60,000,000 tons as the export figure, we are left with a round 200,000,000 tons consumed at home. Of this figure a round 100,000,000 tons is consumed during the year in the domestic fire-grate. We all revel in the blazing fire in our rooms during the winter, but do we reckon on the cost? The volume of heat thrown into the room is but a trifling proportion of that emitted by the glowing coal. The greater part flies up the chimney, together with all the benzol, ammonia, and other valuable constituents of the fuel. Immense volumes of soot pour forth from the chimneys to pollute the atmosphere, disfigure buildings and monuments, while the damage wrought within the rooms to fabrics, curtains and other embellishments runs into millions sterling during the year.