THE 



TROPICAL AGRICULTURIST 



AND 



MAGAZINE OF THE 



CEYLON AGRICULTURAL SOCIETY. 



Vol. XXXIX, COLOMBO, NOVEMBER 15th, 1912, No. 5. 



HARD CURED PARA. 



MR. WICKHAM'S B. MODEL AT PERADENIYA. 

 One of Mr. Wiekham's smoke curing machines, the first to be intro- 

 duced into Ceylon and the East, has been erected at the Peradeniya 

 Experiment Station for the purpose of submitting it to a trial of six 

 months or a year with latex from a definite amount of trees set apart 

 for that purpose. Visitors to Peradeniya interested in the various pro- 

 cesses of coagulating and curing rubber should make a point of studying 

 the working of the smoker and the resulting rubber. 



Difference Between Coagulating and Curing. 



Mr. Wickham draws a clear distinction between the process of coagul- 

 ating rubber by means of reagents as practised in the plantations of the 

 East and the curing of hard Para in the virgin forests of the Amazon ; 

 his contention being that with hard cured the whole of the latex is 

 treated and becomes transformed into an amalgam with the essential 

 oils of the smoke ; whereas with cagulation part of the latex is separated 

 out in the liquor ; and that thus hard cured Para contains certain natural 

 constituents absent in plantation rubber which may account for the 

 qualities of durability and toughness for which it is particularly noted. 



The Process. 



For curing hard Para the Brazilian tapper builds a small oven-like 

 furnace with a hole at the top for the issue of smoke and over this hole 

 close to the heated smoky orifice he suspends his mould, usually a round 

 piece of wood, in the smoke until the surface is well heated and becomes 

 covered with condensed oils from the smoke. He then swings it over the 

 latex tank and with a dipper pours the latex over the mould playing the 

 latter so that it gets evenly covered with a thin coating of latex. Ha 

 then swings back the beam, which is often suspended by a rope from a 

 support above, over the hot, smoky blast, after a few moments' contact, 

 returning it again to receive another floating film from the tank. In 

 this way a block is built up of 10 to 100 or more pounds in weight. The 

 pressure exerted by each additional superimposed layer is an important 

 agent of manufacture. The lump may be left for a few months or a year 

 or marketed at once. 



