Still later the preparation of the "slab" form was displaced by "loaf" rubber. This form was built up by winding together ordinary thin sheets which had been subject to the "cure." Only slight tension was needed, during the operation of winding, to cause close adhesion of the component wet layers, and the final result was a "loaf" or roll dark in colour, and apparently dry when examined superficially. On being cut, even after an interval of months, the middle portion was still so moist as to be quite white. In course of time it was discovered that all the claims made for the process could not be substantiated, and for various reasons (which need not be detailed) most of the estates which had adopted the scheme reverted to ordinary methods of preparation. At the time of writing few, if any, continue to work the process. It appears to be agreed, as the result of investigations, that in no degree does the process yield advantage over ordinary methods. FREEZING PROCESS.--A patent was secured a few years ago to cover a process whereby coagulation was effected by refrigeration. Latex remained for several hours in the refrigerating chambers of an ordinary ice-making plant. The resulting solid mass, on being thawed, yielded a coagulum appearing in no way to differ from that obtained by ordinary methods of coagulation. Provided the process exerted no influence for good or evil upon the quality of the resulting dry rubber, the value of it would appear to depend upon the relative cost of working, plus considerations of capital expenditure and depreciation on the plant. At the present time it would be difficult to imagine that the cost of preparation alone would compare favourably with that sustained by ordinary coagulative methods. Furthermore, beyond the expensive refrigerating plant, the usual machinery of a factory would still be required if the ordinary market demands are to be met. Finally, it has not been found[27] that any advantage in the final physical qualities of the rubber is obtained by the employment of this process. [27] "Preparation and Vulcanisation of Plantation Rubber" (Eaton, Grantham, and Day), Bulletin No. 27, F.M.S. Department of Agriculture. WICKHAM PROCESS.--This process, invented by Sir Henry Wickham, aimed at the production of a rubber resembling Fine Hard Para. The principle employed was that underlying the preparation of the best rubber in Brazil--viz., coagulation of superimposed thin layers of latex by the action of smoke and heat. In essential the machine employed consisted of a rotating drum into which latex and smoke entered. The result was the formation of thin "skins" of rubber which, coagulating _in situ_, formed a mass corresponding to "Fine Hard." That the rubber was fully satisfactory as to quality is acknowledged, but economically and in practical utility the process was unsuccessful, the rate of output being so low.