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to dry rubber quite well and satisfactorily without any artificial heat 

 by the use of some agent that will dry the air. For this purpose 

 I recommend calcium chloride. This substance is made com- 

 mercially on a large scale, it is comparatively cheap being about 

 30/- a hundredweight and it is very effective as a drying agent. 

 The material as bought is in white granular lumps which when 

 placed in open air absorb moisture from the air and the calcium 

 chloride becomes moist and eventually absorbs so much water that 

 a syrupy liquid results. The great merit of this substance lies in 

 the fact that it can be recovered from the wet state by simply 

 heating and thereby driving off the moisture. A simple form of 

 rubber drying shed adapted for use with calcium chloride could 

 easily be made by building a brick chamber capable, when the 

 rubber is turned out in sheet or "biscuit'' form, of holding a 

 month's output, cementing the floor, fitting inside the usual stacks 

 for the rubber, but in addition having above the rubber stacks, 

 shelves to hold iron pans in which the calcium chloride could be 

 placed and freely exposed to the air in the chamber. As the cal- 

 cium chloride absorbed the moisture and became sloppy, the pans 

 should be removed and the water driven off over a brisk fire stirring 

 the mass meanwhile. When quite dry and porous again the pans 

 should be returned to the rubber drying chamber to do their work 

 again. In this way there would be little or no loss of substance, 

 and the air inside the chamber being constantly dry mould would 

 be absolutely prevented and the rubber would dry in half the time. 



The pans if used inside the rubber shed should be placed above 

 the rubber, moist air being lighter than dry. 



A still more efficient system would be to devise a circulation of 

 dry air in the chamber and if this system were adopted it would be 

 best to dry the air before blowing it with fans into the chamber. 

 This could be easily done by causing it to pass over a series of 

 iron pans of calcium chloride contained in a drying box outside. 



The practical details of arrangement of course are easily worked 

 out, I can give sketches to any who intend setting up such cham- 

 bers shewing a good if not the best possible arrangements. 



There are then two chief objections to the method of prepara- 

 tion as at present adopted ; the first is that a considerable weight 

 of mother liquor is retained by the freshly coagulated latex and 

 in the rolled biscuits, and while the watery part of the liquor is 

 dried out the impurities present in solution in that liquor remain; 

 the second is in the mode of drying the biscuits — if dried in the 

 open air there is much putrefaction and development of mould, 

 if heat be used the rubber suffers in nerve. The remedy for the 

 first objection — -adopting the present method of making biscuits 

 and pressing them will be to freely dilute the latex with water 

 before coagulating, thus lessening the concentration of solid mat- 

 ter retained in solution in the water that is not pressed out of 

 the biscuits. The difficulty in drying can best be met by the use 

 of calcium chloride as an artificial drier 



