6o 



Table II. — Tests on Vulcanised Plantation Rubbers. 



Vulcanisa- 





tion 





Sulphur, 



reference 



per cent 



number 







4° 







49 



T 



6 



62 







1 A 







77 





6 



/y 







80 







80 

 03 







°j 



R 



6 



07 







99 







104 



T 



6 



92 







94 







143 



D 2 



6 



144 







IOI 







45 



K 



5 



139 







no 



X 



8 



Mean 



of all tests 



Mean of L, Q, 



Tensile 

 strength, 

 in grms 



Elongation 

 at rupture 

 when original 

 = 10. 



3278 



3129 



3574 

 3133 



2882 

 3015 

 2910' 2933 

 2927J 

 3164) 

 3263^3264 

 3366] 

 3320^ 

 3168 



3499 

 3410, 



3349 



3260) 



3120 



R, T, and D2 



298: 



3428 [3245 

 3169) 

 3324 3324 

 3203 



3i87 



13*4 

 127 



13*9 

 13*3 

 13*2 

 i3*iJ 



12- 4^ 

 12*4 

 127, 

 i3'3) 



12*5 



13- 1 



I2'9J 



13*4 

 13*4 

 137 



14*3 

 13*9, 



12*0 

 13*1 



I3-0 



I3'0 



13-4 



12-5 



12*9 



13-4 



14*0 



12*0 



Elongation 

 under a strain 

 of 1,500 grms. 

 when original 



= 1.0. 



8'3 



f 97 



8-9 



8'2 



IO'I 



77 



8-9 



Table III. — Tests on Vulcanised hard cure Para. 



Vulcanisa- 

 tion 

 reference 

 number 



95 



97 U 

 114 



115 Y 

 124 



Sulphur, 

 per cent 



Mean of all tests 



Tensile 

 strength, 

 in grms 



354iP * 



26 4 6 l 2 8o8 

 2970) 



3118 3118 

 3013 



Elongation 

 at rupture 

 when original 



= 10. 



12*2) 



i 2 -s} 12 5 



£3 12-8 

 12-4) 



Elongation 

 under a strain 

 of 1,500 grms. 

 when original 



= 1.0. 



12*9 



127 



12*9 



IO'l) 



9*8/ 



9*3 



9*3 



9'9 

 9'3 



given above). After washing and drying, the mixing and vulcanisation 

 of the samples was carried out in exactly the same manner as with the 

 plantation rubber. The results of the tests are given in Table III. 



It will be seen that the average tensile strength of five vulcanisa- 

 tions, comprising three mixings, in all of which 6 per cent, sulphur was 

 used, averages 3013 grms. and the elongation 127. Both figures are 

 somewhat lower than those obtained with the plantation rubber. The 

 figures, too, are more irregular. It is far from our intention to draw 



