In the previous chapter I have recounted how the engineer is now striving to conserve rather than to destroy what we throw to one side as of no further use. By inventive ingenuity he is endeavouring to bring home to our local authorities how to extract further utilitarian value from what the household discards. The question immediately arises as to what extent this tendency towards preservation and construction, as opposed to destruction and loss, is being supported in a practical manner by the authorities concerned. It is to be feared that, considered on the whole, the seeds which are being sown are falling on barren ground. However, here and there our civic and municipal authorities, especially those who evince a distinct pride in being numbered among the pioneers of progress, are fully alive to the possibilities of the problem, and are leaving no stone unturned, nor sparing any exertion, to bring home to the public at large that refuse is merely matter in the wrong place. In some instances this reversion to rigid economical methods is not of modern record, the practice of salvage or recovery of abandoned products having been practised along more or less comprehensive lines, as indicated by scientific thought, for many years past. The city of Glasgow is able to point to a convincing record of what can be achieved in this direction. In the years 1908-9 the fathers of the progressive Scottish city derived £41,000--$205,000--from this source, while during the ten years ending 1918 what is commonly regarded as rubbish and useless has been induced to yield no less than £50,300--$251,500. Surely what can be achieved in one city is equally possible of attainment in every other community throughout the British Isles to a greater or lesser degree! Glasgow has evolved its own organization for retrieving and utilising the city refuse and in accordance with the conditions which obtain in the locality. Speaking generally, the system may be described as one of separating the saleable from the unsaleable. Previous to the year 1917 efforts were devoted mainly to the preparation of fertiliser from the contents of the domestic dust-bin, as well as the recovery of tins, but, owing to the high prices which other so-called waste was commanding, and in deference to the national appeal towards greater economy, the reclamation of other materials was taken in hand with highly gratifying results. The refuse of the city is collected in the usual manner and conveyed to the depot. It is weighed upon receipt. It is then dispatched up an inclined roadway to a tipping floor, where the vehicles discharge their loads through shoots. Beneath the latter are disposed horizontal revolving riddles of conical form. The fine refuse and cinders escape through the grids, but the bulky material is carried forward to be ejected on to a travelling conveyor.