666 RUBBER 



(3) Byrne's process; (4) coagulation of latex in shallow 

 trays in a smoke-house, devised by the writer and since 

 by others. 



The Derry Process. This process was originated by 

 Mr. Derry, late Curator in the Botanic Gardens, Singa- 

 pore, and was first worked successfully by Mr. Barrow- 

 cliff, First Assistant Agricultural Chemist, Department 

 of Agriculture, Federated Malay States, on behalf of a 

 Committee appointed by the Government to investigate 

 the process. The principle of the process depends on the 

 coagulation of thin films of latex on a revolving belt. 

 The present apparatus consists of two belts, each 40 ft. 

 long, which are worked by hand and made to revolve in 

 a long smoke chamber. The smoke is generated in an 

 outside furnace and passes into a large pipe on the floor 

 of the building, thence into a smoke-box and through 

 perforated pipes placed immediately under the belts and 

 extending nearly the whole length of the belts. The 

 belts are passed over rollers at each end, with gearing 

 and mechanism to tighten and raise them, and are slightly 

 inclined to the horizontal. Latex is placed in shallow 

 trays on tables which can be raised and lowered by means 

 of a screw; the tables are raised so that the latex in the 

 trays just touches the belts by capillary action and a very 

 thin film is thus taken up. The tables are placed under 

 the rollers, i.e., at the lowest end of the belt just outside 

 the smoke-room, as it would be difficult to operate inside 

 the room. When properly working, one revolution of 

 the belt through the smoke chamber is sufficient for each 

 film of latex, so that the latex can be continuously taken 

 up by the belts. Two very essential factors, on which the 

 success of the process depends, are dry fuel and con- 

 centrated latex containing over 25 per cent, of dry 

 rubber; with the present apparatus a strong breeze is 

 found to be disadvantageous. The rubber is allowed to 

 remain on the belt overnight, stripped off the following 

 morning and rolled together; if necessary it can be 

 allowed to hang for a further period in the smoke-house, 

 but it is not known whether this improves the quality 

 further. The maximum output per belt is about 15 Ib. 

 for a period of six hours. The process can probably be 



