Brought forward 
Magnesia 
Potash 
Soda 
Phosphoric acid 
Sulphuric acid 
Carbonic acid 
Nitric acid 
Chlorine 
Silica soluble in alkali 
Insoluble silicates and quartz containing 
sand separated by washing 
■ ■ 45:^5 
.028 
• • -093 
.147 
.181 
.034 
. . traces. 
. . .001 
.007 
. . 12.049 
coarse 
• 41-635 
100,000 
(Signed) JOHN HUGHES, f. i. ch., 
Analytical Laboratory, 
79, Mark Lane, London, 
April 2 8th, 1899. 
The results of the researches of Mr. Parkin and Mr, 
Willis, on the latex of Rubber-trees have now been published 
and will doubtless be read by every earnest planter. The paper 
contains a great deal of interesting information and many original 
observations and suggestions which are well worth considering. 
Great stress is laid on the preparation of rubber from the latex 
by centi if ugalization and chemical processes. Separation of the 
lubber by centrifugalization was first experimented with by Mr. 
Biffen, in Mexico last year, and further experiments were 
carried out in Ceylon. Para rubber does not seem to work well 
with the machine, requiring a somewhat high rapidity f o separate 
it but the plan seems to be very successful with the latex Jf Cas- 
tilloa and perhaps it might also be used with some of our more 
liquid native rubbers. It is stated that a company has been 
started in Mexico to produce commercial rubber bv centrifu- 
galization. “The advantage” say the authors “of this new 
process are obvious. The rubber can be obtained practically 
pure from tho l&tcx without the admixture of proteids etc 
hence no liability to decay. Since the Caoutchouc particles are 
obtained in a thick cream which can be spread out on a porous 
surface, it allows of the rubber being prepared quite dry in a 
short space of time.” 
Now in the Straits Para rubber sets solid almost directly after 
the latex is drawn off from the tree. To obviate this it is requi- 
site to add a little ammonia and water to keep it liquid, it is then 
filtered twice, heated nearly to boiling point with some acetic 
acid and creosote, and then c‘old water is poured into it when 
the lubber collects in clots which are to be pressed out in thin 
sheets on a porous surface and dried off. It naturally occurs to 
one on reading this that though it is probable that a very supe- 
lior article may be procured by this means the expense of pre- 
