28o 



Test for viscosity accordinf^ to Axelrot. — 10 grammes of the rubber 

 were steeped and disolved in 300 cb. cm. henzol, and the period taken 

 to run through of 100 cb. cm. of the solution taken by an Axelrot 

 viscosimeter, whereby benzol, the running through period of which 

 was taken as l for comparison. 



Singapore I ... ... ... ... 21, 4 



2 ... ... ... 21, 9 



Light Ceylon ... ... ... ... 35, 6 



Dark „ ... ... ... ... 30, 4 



Fine hard Para ... ... ... ... 59, 8 



Congo ... ... ... ... ... 3I» 6 



Breaking Strain and Stretch. — For this test the different kinds of 

 rubber were always mixed in the same proportions, the mixtures 

 vulcanized, and after being cut into rings of the same diameters, they 

 were tested by a Schopper Apparatus for breaking strain and stretch. 

 The residts were as follows per square cm. 





Breaking Strain. 



Stretch. 



Hard cm-ed Para 



... 21, Ks. 



362. 5% 



Singapore sample I 



.. 32. 5 



350, oy 



M * .,2 



. . . 20, „ 



328,75% 



Light Ceylon Para 



... 14. 6 „ 



257, 50 % 



Dark 



••• ^7, 3 



366, 25 % 



Congo 



... 14, 



■hM. 50 % 



Adhesiveness. — A suitable mixture was coated on 



one side of a 



piece of cloth. The coated sides vulcanized together under pressure 

 and tested for the amount of weight necessary to break strips 5 cm. 

 broad. The results were : - 



Fine hard cured Para ... ... ... 10, Ks. 



Singapore I ... ... ... ... 9, „ 



2 ... ... ... ... 9, 5 „ 



Light Ceylon ... ... ... ... 5, ,. 



Dark „ ... ... ... ... 5, 5 „ 



Congo ... ... ... ... 9, „ 



The results are highly satisfactory for the samples sent us, and 

 prove that the material of the Botanical Garden is quite equal to Fine 

 hardciired Para. 



We cannot give at the present moment a definite opinion if the 

 smoking of the rubber is a great advantage, as we have already men- 

 tioned we are not sure if the materials used for comparison taken 

 from the Hevea trees in Ceylon have been so carefully handled and 

 the latex taken from trees of the same age. 



This latter point seems to us to be of much importance, as 

 sample I from 12 year old trees gives a better result against sample 

 2 from 8 year old trees, although it is specially remarked that this 



