42 
THE TROPICAL AGRICULTURIST. 
I July 1, 1899. 
RUBBER- 
Te the Edilof. 
-ITS CULTURE AND PRE- 
PARATION IN TRINIDAD, &c. 
Botanical Department, Tr inidad, April 24. 
To Editors ^'Tropical Agriculturist.^' 
Gentlemen, — I note a reprint in T.A. which 
would probably have escaped notice, had I 
not been a reader of yonr periodical. As it 
was noted in your publication, it is due to 
you that I should send my reply to you also, 
and I trust therefore you will give the enclosed 
insertion, and Mr. Biffen is, I know, a friend 
of your Mr, Willis. — Yours faithfully, 
J. H. HART. 
EUBBEE COAGULATION AND SEPARATION, 
&c., &c. 
Sir, — In the Tropical Agriculturist for March 9th, 
I find an article by Mr. R. H. Biffen, copied from the 
"Journal of the Society of Arts," treating on the 
above subjects. 
The writer exhibits a tendency to decry similar 
efforts as his own, and he uses extracts from the 
Trinidad Bidlctin in a way to mislead those who have 
not that publication in hand ; as he refrains from quot- 
ing the authorship of the articles. Ho should have 
told his readers that Dr. Ernst of Caracas was respon- 
sible for the statement he quotes as being " incorrect," 
and not the editor of the T.B. as he leaves it to be 
inferred for reasons of his own. 
After discussing the value of rubber prepared in 
various ways, Mr. B, jumps to the conclusion that 
Dr, Ernst is wrong in stating that " smoked rubber is 
impregnated with impurity," and decides the fact by 
the prices realised by certain qualities on the larger 
markets for this class of produce. Now ! I happen to 
have an estimate of rubber prepared without smoking 
(Hevea) given by respectable dealers on those same 
markets, who valued it as being quite equal to the best 
smoked rubber, so that a reliauce upon this method 
of estimating quality is proved unsafe, and it may well 
be that, later on, when buyers have become accustomed 
to it, pure rubber will sell at higher prices than the 
smoked product. 
Equally unsafe is Mr. Biffen's statement that the 
juice of the Moon-flower is " alkaline," for I have a 
qualified analyst's certificate that fresh juice sent by 
me was found " slightly acid." Equally fortunate is 
Mr.B.'s assertion that Castilloa latex will not coagulate 
by the addition of acid, as it has been found to coagu- 
■ late by the addition of acetic acid (Biffen in Aun. Bot. 
pp. 165 et seq). 
The point of Mr. Biffen's conclusions in his article 
in the Annals of Botany is " that the cause of coagula- 
tion must be looked for in the medium in which the 
rubber particles are suspended," but unfortunately 
for this theory it has been abundantly proved that not 
only can rubber be coagulated when the albumenoids 
are removed, but a better class of rubber produced. 
An attempt follows to ridicule the statements as 
to the character of land suitable for various rubbers, 
and accuses us of " slight confusion" in the Trinidad 
Bulletin, As a matter of fact the statements are quite 
sound, and the confusion only exists in the v^riter's 
brain. Hevea will grow well in places never inun- 
dated, notwithstanding the fact that it is found in 
places regularly flooded, and this can be proved by 
trees growing in Trinidad, which have been found to 
stand drought with impunity, and have never been 
flooded. 
I can well afford to pass without irritation the 
remark made on my supposed "re-discovery" of a 
method, for the method differs so much from that 
described by older writers, that it cannot be placed 
in (de ^m,^_ category. i( is » method of washing. 
in it 13 true, but a very different method to any 
tormerly described, in fact miv well be compared 
fu ^^'^s]»Dg of the steam laundry as contrasted 
witn that of the peasant at the river side. 
Notwithstanding what is said by " Le Caoutchouc " 
(p. bj rubber prepared by this process is of the highest 
quality, as u is found possible to rash it quite free 
troni corps etranyers. 
Mr. Biffen claims that his machine separates the 
lubber particles by centrifugal action, but the real 
lact IS, tiiey are brought to the surface by centripetal, 
not centrifugal action. 
The insertion of the word isic) might also have 
been readily avoided by the writer, had he noted 
tnat the word "or" should have been substituted 
tor the word " anj." 
I now come to a remarkable statement where Mr. 
J3inen says that research work should tend " to 
prepare rubber free from the other constituents of 
ine latex How this is to be reconciled with the 
previous dictum of the Annals of Botany is not quite 
Clear. It there says " The action of centrifugal force 
ettects the separation of the rubber, and from the 
lailure of the processes usually employed, involving 
ine use of chemical re-af^euts to bring about the clot- 
ting of the separated and washed rubber particle? we 
must infer that the cause of the coagulation must he 
tootied tor in the medium in u-hich they ore suspended.- 
Again we are told that " the coagula in forming 
gather up the rubber particles " . . . " in the same 
way as the white-of-egg gathers up particles in suspen- 
sion when clotted for the purpose of clearing jellies. ' 
it must be concluded therefore that Mr. Biifeu has 
auanrJoned the position he formerly took up, and is now 
cievoted to the task of removing those very constituents 
ne tormerly slated were essential to coagulation but 
wtiich he at the same time proved could be dispensed 
with for he told us that they could be " brought into 
fi^n!! iP?^ pressure, by heating and by evaporation 
^4' ^''^y "^oes he use the words -brought 
into a solid mass "? and not the word coagulation ? 
'*ir. Bitfen records his success in preparing rubber 
I a physical process. He started by requiring 
albumenoids for coagulation, but now he is recom- 
mending separation by a physical process ; and has 
auopted what is actually the basis of the hydro pro- 
cess, which he facetiously accuses me of having 
rediscovered. I might with equal propriety ask him 
Whether he re-discovered the Babcock machine. If I 
re-discovered ! so has he. I separate by water, he 
by physical methods, but I dry by evaporation ! bo 
aoes he. His rubber is free from impurities ! so ia 
mine. His method requires a machine, so does mine. 
Again his rubber is free from smell, so is mine, and 
I'lge quantities can be prepared in a day by simple 
apparatus, while it would take a powerful engine to 
m-ive the machine to get through a similar quantity 
by centrifugal action. The quality of my rubber is 
equal to that prepared by other physical processes, 
as a voucher for which I am quite prepared ^to 
submit samples for test and the " merits or demerits 
of tlie system" do not rest with me, but with those 
who can judge of its value by actual practice ; Mr. 
Bitten states the contrary. 
Mr. Biffen repudiates statements made in Trinidad, 
but no one has asked him to be sponsor for them, 
ile must however allow me also to repudiate the points 
conveyed by his remark that " a copy of his machine 
was exhibited without his consent or knowledge." 
As a matter of fact the machine was no " copy " any 
more than his primary effort was a " copy" of the 
Babcock ; but was of different construction, and a 
vast improvement upon his model, as he knows, for 
drawings of the improvements were placed in his 
Au " S^^'^^ock " machine was never patented, 
and there are consequently many modifications of it, 
among which are the forms under discussion which 
can hardly be called inventions, for such adapta- 
tions are being made daily all over the world, for the 
separation of materials of different densities, 
I may be liable to a protest from Lefebre for 
pirating Iiis ancient washing method , I may perhaps 
expect ^ raid from CeHtcai American Ic^ian^ 
