an invention “for the rapid coagulation of fresh latex from rubber 
“trees. ” A few words explaining my method may perhaps be of 
interest to the readers of the Bulletin. 
So far we know of 3 modes of coagulation. 
1. Spontaneous coagulation such as takes place on the tree 
from the heat of day, producing scrap. 
2. Coagulation by chemicals. 
3. Coagulation by artificial dry heat such as that employed by 
the Amazon native. 
I make no mention just now of coagulation by formaldehyde 
recently prcconised by Dr. Weber, to which Mr. Pears has lately 
drawn the attention of planters ; nor of coagulation by centrifugal 
action. I shall come to them presently. 
Spontaneous coagulation is uncertain, unclean and wasteful ; 
decomposition is liable to occur in the milk if exposed in any quan- 
tity, especially that of Hevea which is apt to turn putrid in a few 
hours. 
Coagulation by chemicals is a handy/ clean and expeditious way 
of preparing rubber, but we cannot blind ourselves to the fact that 
it has not yet established its efficiency to the satisfaction of the 
rubber trade. There is a keen suspicion abroad that, as Dr. 
Weber says “ coagulation of rubber by acids results in differentia- 
ting it more or less from the original product’' and I believe it is 
a fact that its behaviour in the manufactured state does not tend to 
give it a good name. If that is so, why, the treatment of rubber 
latex by acids must go to the wall. 
We have to consider now the third method, viz. coagulation by 
artificial dry heat as employed by the Amazon natives. The method 
is so well known that there is no need to describe it here, but it 
will be well to settle one point in connection with it, i.e the precise 
action of the smoke on the latex. 
It was thought at one time that the smoke of the nuts often used 
by the natives had a strange and peculiar property of coagulating 
the milk independently of the heat evolved ; but this is not so. As 
consul Temple says : “It is a mistake to suppose that all, or, even 
“ a large proportion of the rubber coming from the Amazon is cured 
“in this way (with the nuts). It is on the contrary very rarely 
“ that the rubber cutter will be at the trouble to collect these nuts ; 
“he nearly always prefers to use wood chips which give him less 
“ trouble to procure. " 
We may infer from this that any white smoke developing suf- 
ficient heat, and not actually deleterious, will do for the purpose; 
and further that the smoke coagulates not because of any virtue of 
the nuts or of the material employed, but simply because it is hot, 
just as spontaneous coagulation is brought about by the heat of 
day. The native employs smoke in preference to an open fire be- 
cause of the risk of burning the rubber, a frequent occurrence even 
in the case of smoke coagulation. The .smoke has, moreover, 
antiseptic qualities, but, as a set-off against this, the particles of 
soot which it contains, constitute in themselves an impurity. I 
think the main secret of the spccess of the Para method is this ; 
