6i 
rigorous conclusions from these series of tests, and we do nomfer that 
caoutchouc in the plantation Para is superior to that m the Am^man 
hard cure Para merely because >n an average! >f>— 1 ^erot tests 
some^ modhicatio^when SKd * 
sui-s »ssr.s s&S™ 3 
vulcanisation so as to bring out the best results m both cases. 
A considerable amount of work on these lines is ^ogress and 
in the plantation products will prove to be at f ® r we find that the 
vulcanised product obtained from the best prepared block. 
We have examined the distensibility of vulcanised jptartrtum 
rubber under increasing strain, and the results are plotted in the form 
of a curve. 
As in the tensile strength tests, a sheet of rubber i mm. thick 
ss scp.-a -“= s:s!r^.=£- .. 
weights were put into the pan. 
We have also made some preliminary tests on sheets of block 
is, approximately: — 
Caoutchouc 
56 per cent. 
11 
28 
Zinc oxide 
Lithopone 
Pitch ... -• •• 1 ” 
and sulphur, 8 per cent., reckoned on the caoutchouc. 
Mixing J consisted of 50 grms. of plantation block caoutchouc 5 
grms. sulphide of antimony, and 2 grms. sulphur. The results 
obtained are given in Table IV. 
