The rate of output of scrap-washers will depend mainly upon the speed at which they are driven, and when ordering the equipment it would be advisable to state the ordinary speed of the back-shaft, length of drive, etc. It does not follow that the larger the rate of output, the greater is the efficiency of the washer. The point is not as to what quantity of rubber can be taken out per hour, but what quantity is actually freed from impurities. It is advisable for the superintendent to obtain a thorough knowledge of the general construction and principles of the particular scrap-washer employed. In the past it was not uncommon to find superintendents innocent of the fact that a certain type of washer possessed movable parts upon which the efficiency of the cleansing largely depended. It was often found that these parts, which were intended to be removed and cleaned at intervals, had become firmly fixed and could not be removed for inspection. It must be recognised also that the machines are liable to considerable damage if extraneous substances are allowed to enter--for example, tapping-knives, stones, pieces of iron, spouts, etc., which are sometimes present in the loose scraps of rubber or shavings, owing to the carelessness of coolies. Under the best regulated-system, such accidents occasionally occur, but a great deal of trouble could be avoided by having it understood that each charge must be sorted over before entering the washer. Again a deal of extra work, and much wear and tear, is caused by the _abuse_ of the scrap-washer--_e.g._, in the cleansing of earth-scrap. As this reaches the factory it often contains a quantity of internal or adhering earth. Before entering the washer a good proportion of the external soil could be removed if the scraps were thrown into a tank and given a thorough soaking and stirring. In a similar manner dry bark-shavings, which have been allowed to accumulate, could be softened. In the actual working of scrap-washers instructions are generally given by the makers. These sometimes advise the introduction of warm water (or of steam into the cold water supply) for an interval during the working of each charge. Where possible, such instructions should be followed, as by this means the individual pieces of rubber are massed together, in the final stage, into a "sausage" form which is easy to transport and to manipulate in the ordinary crepeing battery. COMPOUND CREPES.--The attitude of both buyers and sellers with regard to the types of lower grade rubbers appears to be changing. In the past, from any one estate there might be obtained as many as six grades of crepe below No. I. These comprised: (1) A pale rubber (often streaked) obtained from coagulation of cup washings and bucket rinsings. (2) A pale rubber (often streaked) obtained by coagulation of the skimmings from the surface of the No. 1 latex.