The tardy recognition of this fact is responsible for a curious reversion in practice. The open-air sifting of house refuse for the recovery of substances possessed of commercial value was unequivocably condemned from health motives, as previously mentioned. Yet, in order to recover these articles, some system of selection and hand manipulation are inevitable, notwithstanding the high degree of intellectuality to which machinery has been advanced. But the old system of hand-picking was primitive in its simplicity. The circumstance that household refuse, both organic and inorganic, possesses virtues which the vogue of the destructor caused to be blindly ignored, has been responsible for a manifestation of marked ingenuity upon the part of the engineering profession. The necessity to recover every ounce of material possessing a market value was never so acute as it is to-day. Supplies are short and are likely to remain inadequate for some time to come, while the high level of prices is apt to compel more rigid economy. Yet the strains encountered in this direction may be very sensibly lessened by the practice of salvage along more intensive lines. It would seem as if refuse recovery were destined to develop into a highly specialized branch of the engineering craft. Hitherto for the most part the engineer has confined his efforts towards garbage-disposal by destruction, but the new tendency is far more logical and deserving of every encouragement. Certainly it is a field in which abundant scope is offered for brilliancy and ingenuity of thought. This is demonstrated by the activity of certain firms, more particularly of one in the North of England, the guiding hand of the destinies of which has evolved a complete recovery plant, having many decidedly ingenious features, and which is already being installed by certain of our more progressive corporations and municipal authorities. This plant is self-contained, and, so far as is feasible, is automatically operated. While hand-picking cannot be entirely eliminated it has been reduced to the minimum. The system adopted facilitates the task, and renders hand-picking as congenial as the peculiar conditions will permit. Furthermore it is an individual entity. While it can be established in an isolated centre it can also be coupled up to the existing dust-destructor, or power-generating station if preferred, thereby complying with the general desire to centralize municipally-controlled installations. This is certainly a powerful recommendation, because it avoids superfluous transport and handling.