vi PREFACE 



producing industry, IVIr. Brown brings to the task the 

 knowledge gained by over ten years' continuous study 

 of the subject, and the special advantage of possessing 

 both botanical and chemical qualifications for the work. 



The successful production of Para rubber in South 

 America is more than two centuries old, and it is still 

 mainly conducted on the most primitive lines and with 

 the wild trees of the forest, which are of great age. So 

 far as the actual preparation of rubber is concerned, 

 these primitive methods have succeeded in placing on 

 the market a material which is on the whole well suited to 

 the requirements of the manufacturer, so much so that 

 " fine hard Para " obtained from the wild trees of South 

 America is stUl the market standard of the material. 



As is the case with nearly every material obtained 

 from wild and naturally distributed plants, as soon as 

 the demand for the substance is large, it is necessary, 

 chiefly for convenience of collection, to grow it in planta- 

 tions, and the modern industry of rubber production 

 involves the successful management of trees gro\^Ti on 

 the plantation system. In this sense rubber-growing 

 is a new industry, as to which there is little or no previous 

 experience to guide, and therefore the problem of the 

 successful growth of forest trees under plantation con- 

 ditions has to be solved by the use of the scientific methods 

 of observation and investigation. 



The proper methods of growing and manurmg, the 

 best times and methods of tapping, the nature of the 

 parasitic and insect attacks to which trees in plantations 

 are subject, have all had to be discovered, and on these 

 subjects there is little or nothing to be learnt from 

 previous forest experience. 



Althougli the primitive methods of curmg and pre- 

 paring rubber from the latex practised in South America 

 are eminently successful, it cannot be doubted that 

 these methods are capable of simplification and also of 

 improvement. Rubber as hitherto known to the manu- 

 facturer is a mixture containing many otiicr ingi'edients 

 than the true caoutchouc of the chemist. To a large 

 extent it is still a matter of doubt as to what is the 

 l)enoficial influence, if any, of the proteins, the resin, 

 and the olhor companions of caoutchouc on the physical 

 properties ot the material. Moreover the exact nature 



