It is impossible to lay down any general rules for the guidance of estates, as the timber available varies so widely in nature. Experience must be the only guide, and it should not be difficult to obviate the defect. Even so, there must be minor differences between the results obtained on estates, so that it is not possible to make strict estimations of the smoke-curing period by an examination of the surface appearance of rubber, even under the best of conditions. Some estates find that the rubber has a distinct gloss in ten days, while others may smoke-cure for twice that period without difficulty. Evidently, therefore, the question of available fuel is of prime importance. It may be remarked that very satisfactory results are always obtained from the use of fairly dry timber obtained from thinned rubber trees, mixed with the "dead" timber of old logs and stumps found on the estates. Obviously if a smoke-house has a superabundance of furnaces, producing more heat and smoke than is required, glazing will result. The point is tested by the average temperature maintained and the average rate of drying. The result of a high temperature would be the possibility of volatile tarry matter being driven in excess to the upper chamber. That this effect is eventually produced even at optimal temperatures is evident from an examination of the wood-work within the upper room. It is clear, also, that the rate of combustion exerts an influence. In a general sense a rapid consumption of fuel would augment the quantity of tarry matter passing into the upper chamber over any given period, and the possibility of glazing would be increased. On the other hand, it is possible that a surface glaze might be formed if the temperature were uniformly too low, especially if the rubber were rather thick. The rate of drying would be so slow, that if a timber rich in tarry matter were employed, the rubber might be exceedingly glossy. In order to guard against the appearance of a heavy glaze, then, the following points must be observed: 1. The fuel must be carefully selected by experience. 2. The sheets must not be thick. No sheets should be thicker than 1/8 inch measured in average section across the ribs. 3. The temperature must not be too high. An average working temperature of 120° to 125° F. should be ample. 4. If the sheets are fairly thick, a low average temperature should be avoided. No lower average than 110° F. should be allowed.