668 RUBBER 



of crude tarry and creosotic substances and pyroligneous 

 acid respectively, are vapourized by dropping on the 

 heated plate, and the vapours produced are led through 

 a pipe into the smoke chamber. The period of treatment 

 is only two to four hours, after which the rubber may 

 be hung for twenty-four hours and shipped without 

 further drying, or it may be hung to dry in an ordinary 

 drying house before dispatch. When this machine was 

 first introduced it was used for the smoking of crepe 

 rubber, but the demand for this having ceased, and the 

 fact that the process was not taken up to any extent, 

 due probably to the royalty charged by the inventor or 

 the syndicate holding the patents, has caused the adoption 

 of different ideas, the most important of which is the 

 smoking of " slab " rubber. Latex is coagulated by the 

 ordinary method used in preparing sheets in rectangular 

 troughs or trays; the thick, soft slab of rubber is then 

 lightly hand-rolled and is placed immediately in the curing 

 shed, lying flat on the shelves or racks, smoked for two 

 and a half to three hours by means of the fumes from the 

 Byrne machine, turned over and smoked the following 

 day for a similar period, and then allowed to dry without 

 further treatment. The idea is a step in the right direc- 

 tion; but, except for rapidity, it is probable that slab 

 similarly treated in an ordinary smoke-house would pro- 

 duce a rubber possessing equally good physical properties. 



A Byrne machine has been lent to the Department of 

 Agriculture, Federated Malay States, by the Syndicate, 

 and experiments in several directions will be carried out 

 shortly, such as the utilization of the fumes for curing 

 latex on belts in the Derry process, and the coagulation 

 and curing of latex in shallow trays in the curing shed. 

 The racks in the curing house are being erected on wheels 

 and placed on rails so that they can be removed easily 

 from the curing house for loading and unloading. 



Smoke Coagulation of Latex (Author's Process). 

 Experiments were first carried out in 1911 with the idea 

 of coagulating latex in thin layers in shallow trays in 

 an ordinary smoke-house, but were only carried to a very 

 preliminary stage at that time, as it was considered desir- 

 able to wait till samples could be vulcanized and tested 



