SMOOTH-ROLLING.--It is advised that, after hand-rolling, the coagulum should be passed through at least two machines having smooth-rolls. On some estates three such machines are employed. The purpose of this procedure is to reduce the thickness of the coagulum gradually. The same could be effected, of course, on one machine; but obviously the distance between the rolls would have to be readjusted at each operation and for each piece of coagulum. Apart from the time thus wasted, there is the certainty, in view of the rough adjustment of the machines, that the chances of obtaining uniformly thick sheets would be slight. The machines should be arranged as a battery, with the marking rolls at one end, so that the operations are consecutive. It is erroneous to imagine that heavy machines (such as those used in crepe preparation) are required. Light machinery only is necessary for sheet-making; but any available heavy smooth-roll machines in a crepeing battery may serve admirably for the purpose. MARKING.--Heavy machines are unnecessary for the purpose of putting a pattern on sheet rubber. If the rubber has been properly prepared a light pair of rolls is capable of exerting sufficient pressure to cause a good upstanding pattern. Rolls are cut in various designs: some with "diamond" grooves on both rolls; some with grooves of varying width and depth encircling the circumference of the rolls, thus creating a "stripe" effect on the rubber; and some with diagonally-cut spiral grooves placed closely together. The last has the greatest vogue at present, while the first has almost gone out of favour. An objection lodged against the second design is that the edges of the grooves sometimes cut through the rubber, so that the dried sheet divides in strips. It would appear in such instances that either the coagulum was too thin and soft, or that the grooves had been cut too deeply and sharply. In any case the choice of a design is an arbitrary matter, and should depend upon the effect produced on the rate of drying and the general appearance. The popular "close-cut spiral" roll is machined with varying measurements, but the usual design has grooves 1/8 inch wide by 1/8 inch deep and 3/16 inch apart. Many estates have a particular "brand" cut in the middle of the rolls for purposes of identification. If this is done it is advised that the main grooving of the rolls be carried into the "branding" strip; otherwise grip will be lacking on this portion, and a certain amount of "cockling" of the sheets will result.