Abstract In 1927 rumors were heard from different sides regarding a supposed decrease in tensile strength of plantation rubber. These took such a form that The India Rubber Journal took the matter in hand and published a review of data, furnished by different manufacturers and experts. We gave a short review of figures for Java plantation rubber for the years 1923-1926, from which no deterioration in tensile strength was to be seen; on the contrary, the figures showed a slight increase and the conclusion was that, at least for Java plantation rubber, there was no question of deterioration, as was to be expected for anybody conversant with methods of preparation on estates, which are more and more standardized and improved upon. We are now able to supplement these figures with the averages obtained in routine testing in our station during the years 1927-1929. The figures are: