May 1907.] 



2fi2 



GUSWIS, RESINS, SAPS AND EXUDATIONS. 



CEYLON PARA RUBBER. 

 Ia drawing comparisons between Ceylon Para and Brazil Para regarding 

 their respective keeping qualities, G. v. d. Kerckliove, in the " Gummi Zeituug," 

 recommends coagulation by smoke for the former as is employed for the latter. He 

 further affirms that Amazon Para is of a more elastic nature than Ceylon Para, and 

 that it is less liable to become damaged. As long as the consignments of Ceylon 

 Para are small, the quality of the product remains satisfactory; it is when the 

 quantity is increased that heat is developed, with its consequent injury to the 

 rubber. By coagulating the latex of the Hevea obtained in Ceylon by smoking as 

 in Brazil, the author maintains that the keeping qualities of the Ceylon Para would 

 be greatly increased. Ceylon Para being an extra pure, but very dry, rubber, by 

 reason of the way in which the latex is coagulated, is more easily influenced by heat, 

 pressure in packing, long stocking, etc., than other rubbers, as most rubbers 

 containing a little moisture keep better than the extra dry sorts. A rather different 

 is held by Dr. Esch, who is of the opinion that a smoked rubber keeps better 

 when dried somewhat. According to his experience, Ceylon Para is not subject to 

 over-heating, but if insufficiently cleaned and badly preserved it acquires an 

 objectionable smell, which must not be confused with over-heating. If Ceylon Para f 

 when properly prepared, has an inclination to become heated, it is quite as likely 

 that signs will be given of it in small parcels as in large. Perhaps rubber from the 

 ficus trees, which has a known tendency to appear over-heated, has been confused 

 with Para rubber. The Ceylon method of coagulation has been praised by French 

 experts, and the writer considers that a good, properly cured Ceylon Para is equal 

 in elasticity and durability to Amazon Para. The cause of over heating has been 

 ascribed to the presence of albuminoids, so in selecting chemicals to bring about 

 coagulation choice must be made of those which retain these bodies in solution # 

 In conclusion, Dr. Esch states that the uses to which Ceylon Para is put speak highly 

 for its elasticity ; further, this rubber vulcanizes with equal facility to Amazon Para, 

 and he has never found it to retain more than 3 per cent, of resin.— India Rubber 

 Journal. 



[So far as we have been able to find, the great use of Ceylon and Straits 

 rubber, clean and dry as it is, is, as we pointed out would be the case some years ago, 

 for solution, and when that market is overstocked, there must be a fall in price. 

 But already the new "wet block," though only in its infancy, is meeting with great 

 avour . One manufacturer says that it is " practically fine hard Para, and he desires 

 nothing better," while a recent large consignment of Vallambrosa wet block, smoked 

 on the outside to preserve it, and containing 11 per cent of moisture, sold for 5s. 10d., 

 per lb. a price as good as 6s. 6|d. for biscuits.— Ed.— T. A .] 



PROSPECTS FOR GUAYULE RUBBER. 

 The great drawback to the extensive employment of guayule rubber has 

 been the large percentage of resin it contains, great difficulties being encountered in 

 extracting the rubber, together with the elimination of the attending resins. Added 

 to this defect are other objections, namely, its high proportion of ash, the invariable 

 presence of large quantities of organic impurities, and finally, its intense smell. At 

 the same time, however, the pure rubber exhibits all the properties and attributes 

 of the best qualities- But it would appear that the employment of guayule rubber 

 is now emerging from the experimental stage into one of high practical utility. In 

 giving a detailed account of the history of this product up to its most recent 



