76 THE PREPARATION OF RUBBER 



remain in good condition. In some cases in which the 

 rubber is prepared in the form of lump by natives no 

 attempt is made to get rid of the water included in the 

 mass of freshly coagulated rubber, with the result that 

 the lumps remain very porous and have their cavities 

 filled with the serum of the latex ; such rubber reaches the 

 market in a very moist condition and is extremely liable 

 to deteriorate during transit. In certain instances, how- 

 ever, the natives cut the lumps of freshly coagulated 

 rubber into thin strips which are suspended in the roof 

 of a hut, with or without a fire below, and when dry 

 the strips are rolled up into balls or masses of different 

 shapes. 



In the case of the balls of Landolphia rubber, which 

 are formed by winding together the thin films of freshly 

 coagulated rubber from the incisions, the drying is some- 

 times facilitated by cutting the balls open. If this is 

 not done, the rubber in the interior of the ball remains 

 white and opaque, whereas the outer layers become 

 reddish-brown and translucent. 



Sometimes the requisite amount of drying is obtained 

 by the method of preparation adopted, as in the case of 

 the smoking process used for Para rubber in South 

 America. 



No definite rule can be laid down as to the amount 

 of moisture which may be left in rubber, as the per- 

 centage varies very considerably in different forms. In 

 the case of fine hard Para rubber from South America, 

 prepared by the smoking process, which has an antiseptic 

 action, the amount of moisture ranges from 10 to 20 per 

 cent., whereas plantation Para is usually placed upon 

 the market in an almost dry condition, containing, as a 

 rule, less than 1 per cent, of moisture. In all cases, how- 

 ever, the rubber should be dried sufficiently to preserve 

 it from deterioration during transit, as if packed in a too 

 moist condition it will develop mould and become dis- 

 coloured and injured in appearance. 



It is of the utmost importance that rubber sliould not 

 be exposed to direct sunlight or to too high a temperature 

 during the drying process, as either of these conditions is 

 liable to cause the rubber to become sticky. On planta- 

 tions special drying-sheds, from which sunlight is excluded, 

 are usually employed. In some cases these consist 



