The installation yields from 12 to 15 tons of grease throughout the twenty-four hours, working, of course, being continuous. This product in the days before the war commanded from £8 to £10--$40 to $50--per ton, but the price is now higher. The sludge-cakes find favour as a fertilizer, mainly from the fact that they are free from lime and carry only from 28 per cent. to 30 per cent. of moisture. This residue fetched from 3s.--75 cents--upwards per ton at the works in pre-war days, when a healthy export was recorded, the product being shipped in appreciable quantities to France and even to the Southern States of America. The output of cake averages from 50 to 60 tons per day. In addition to proving useful as a fertilizer it has been found to furnish, when blended with coal-dust, a serviceable fuel. The revenue derived from this example of sewage industry is certainly such as to attract widespread attention. In the early days of the process, when only two presses were maintained to establish its possibilities, the grease sales reached £222 10s. 6d.--$1,112.62--per annum. In 1911 the annual revenue had risen to a figure ranging between £20,000 and £30,000--$100,000 and $150,000--from the enlarged battery of presses. When the new works were opened it was anticipated that the Corporation would be deriving £50,000--$250,000--a year from the sale of the products derived from its sewage upon the attainment of the designed maximum output. Up to the year 1911 the total sales amounted to no less than £100,000--$500,000. From the recital of these figures it must be conceded that Bradford has a very profitable commercial enterprise in its sewage works. Yet even the foregoing figures are undoubtedly capable of improvement owing to the advances made in the whole issue of the recovery of fats from wastes. The pressing system, even when conducted along the most modern lines with up-to-date plant, leaves much to be desired in point of yield. Under the most favourable pressing conditions at least 10 per cent. of the original volume of grease is left in the residue. The presence of this grease reacts against the value of the residue as a fertilizer, grease being the bugbear of the farmer. With the latest process for grease extraction this content can be reduced down to 1 per cent. Not only does this represent an increased yield of 9 per cent. of fat with its attendant enhanced financial return, but it gives a fertilizer which, being exceedingly low in fat, appeals more strongly to the farmer, and accordingly is able to command a higher price. This fact appears to have become appreciated by the Bradford authorities according to recent developments.