It is seldom one encounters a case nowadays in which the "marking" is unsuitable, but a few estates may be using an old type of patterned roll on which the full diamond grooving is cut. As this appears on both sides of the sheet of rubber, and as the ribbing does not coincide, a blurred effect is seen when the sheet is viewed against the light.
THICK ENDS, "SHEET CLIPPINGS."--It rarely happens, even with good equipment and average supervision, that the preparation of smoked sheet is unaccompanied by slight defects. For instance, in spite of rules and regulations regarding manipulation of the coagulum, it is not uncommon to find that some sheets, after rolling, have slightly thickened ends. In the ordinary course of events these might delay drying considerably. It is the practice on some estates to cut off these thickened ends while the rubber is still wet. The pieces are then machined into crepe form, but as no sodium bisulphite may have been used, the resulting rubber cannot be classed as No. 1 Standard Crepe.
The other alternative is to trim the ends when the bulk of the rubber is thoroughly smoke-dried. The moisture containing portions are then returned to the smoke-house until dry, and are subsequently packed without further treatment as "smoked-sheet clippings." It will be plain that, except in the particularity of form, these clippings differ in no degree from the original sheets; and, owing to extra smoke-curing, may arrive in even better condition. One must be prepared, however, to find that a slightly lower price is offered. Whether the price obtained would be comparable with that commanded by the crepe made from wet sheet slipping would depend upon general ruling market conditions, and the degree of care exercised in guarding against the inclusion of any inferior pieces of rubber. In ordinary factory practice, there could be no room for abuse under the latter clause.
OTHER INFREQUENT DEFECTS.--This chapter will be closed with a reference to other small defects which, although infrequent, cannot be classed as minor complaints. In point of fact, when they occur, they assume an importance, in the eyes of the consumer, which is not, perhaps, sufficiently appreciated by producers.