JAMAICA- 



BULLETIN 



OF THIi 



BOTANICAL DEPARTMENT. 







Vol. VI 



New Series, j 



JUNE, 1899. 



Part VI 



METHODS OF PREPARING RUBBER. 



By R. H. Biffen. * 



So much has been written within the last few years on the subject 

 of indiarubber, the sources of our supply, and the possibility of acclima- 

 tizing the best-yielding trees in our colonies, that at first sight it may 

 appear that there is little more to be said. A study of the methods in 

 use for preparing rubber from the latex, or milk, may however be of use 

 to many interested in the formation of plantations, especially if some 

 attention is paid at the same time to the inaccurate statements made in 

 some recent publications, which apparently have disregarded the valu- 

 able series of papers on the subject contained in our one journal de- 

 voted to economic botany, the " Kew Bulletin". 



The methods in use at present are either the out-come of the limited 

 experience of uncivilised peoples, or the application of experiments 

 made without paying due attention to what is known of the chemical 

 constitution and physical properties of latex. As a good example of the 

 latter we may take the experiments of Morisse** who found that 

 coagulation was brought about in the latex of Hevea by the addition of 

 alcohol, phenol, hydrochloric acid, nitric acid, sulphuric acid, calcium 

 chloride, ferric chloride, corrosive sublimate, etc. As the outcome of 

 these experiments a mixture of phenol in alcoholic solution, and dilute 

 sulphuric acid was recommended as a coagulating agent. 



The latex is, as a general rule, a thick, white fluid, composed of 

 small particles of rubber in suspension in a clear watery solution of va- 

 rious substances. Unfortunately, only the latex of a few trees has, as 

 yet, been chemically examined when fresh. 



* Journal of Society of Arts. 



** Seeligman, Lamv, et Falconuet ; " La Caoutchouc et la Guttapereka, 

 Paris, 189S, p. 68. . * 



