656 
THE TROPICAL AGRICULTURIST. [April 1, 1904. 
upwards, were of much better quality than tlie pre- 
ceding, though the amount of re=in present, 13'8 
and 8'3 per cent., is still higher than is usually 
found in the best qua ities of lljia variety of rubber. 
Specimen (e) is the Ijest of the series both as regards 
chemical composition and physical characters. 
COMMERCIAL VALUATION. 
The two Caatilloa rubbers (d) and (e) were sub- 
mitted to brokers, who were informed of the results 
which had been obtained by chemical examination. 
The brokers report that at the present time the rub- 
bers would have the following values in the London 
market : — 
(d) OastilUoa .. 2s. 4d. per pound 
(e) „ .. .. 2s. 9d. 
They observe that there has recently been a con- 
siderable scarcity of medium qualities of rubber in 
the London market, and that consignments of similar 
quality to these samples would command a ready sale 
at the present time. 
The results furnished by the examination of the 
various samples of Castilloa rubber, so carefully and 
systematically collected and prepared by Mr, iBart, 
are of considerable scientific interest, and are of 
obvious practical importauce, especially in establish- 
ing the conditions which must be secured in order to 
produce rubber of first-rate quality. 
samples of castilloa rubber peepaeed by 
webeb's method, 
This sample of rubber of Castilloa elastica was 
forwarded to the Imperial Institute by the Govern- 
ment of Trinidad, and had been prepared by the 
Superintendent of the Botanic Department accord- 
ing to the method suggested by Dr. C. O. Weber, 
which consists in the addition of formaldehyde to 
the creamed latex. The following particulars were 
supplied regarding the exact procedure adopted : — 
" Latex from Uastilloa trees 14 to 16 years old 
500 oc, creamed in four times its volume of clean 
water, three times in succession to remove abumin- 
oids. Added 20 co. of commercial formalin to 
latex when creamed on last lot of water. No 
cohesion took place until 96 hours after mixing. Rub- 
ber then lifted and pressed, Cold water wag used." 
The specimen was a semicircular cake, 4 in. in 
diameter and 1 in, in thickness, which weighed 
about 50 grams. Externally it w.is a light brown 
colour, but wibhin it was quite white, perfectly dry 
and free from foreign matter. The rubber exhibited 
very satisfactory physical properties ; it was not sticky, 
and was very elastic and tenacious. , 
The following results were obtained on chemical 
examination : — 
Sample as Calculated for 
received. Dry Material. 
Per cent. Per cent. 
Moisture ... .. 9'5 — 
Caoutchouc... .. 826 91 '2 
Resin ... .. 7-4 S-2 
Dirt ... .. 0-5 0-6 
A8h(inclnded in dirt) . . 0 26 0-29 
These figures are practically identical with those 
furnished by sample (e) of the previous consign- 
ment, which was prepared by coagulating the washed 
and creamed latex by alcohol. The physical charac- 
ters of the two specimens were also very similar, the 
only difference being that the sample prepared by 
Weber's method was much lighter in colour. 
The brokers also regarded the two specimens as cf 
equal value, and quoted for each a price of 23. 9d. per 
pound. 
THE HEVEA SEED IN COMMERCE. 
A BY-PRODUCT ON THE RUBBER PLANTA- 
TION. 
Rubber planters are well aware that the mature 
Hevea tree (the Para rubber tree) produces large 
quantities of seeds, far more than are required for 
caising yoang plants for exteusiona on the plauta« 
tion It was known that the seed contained a certain 
amount of oil, and a proper and economic use for the 
surplus supply of seed appeared a necessity. In the 
Malay States experiments were tried with them, we 
believe, and a meal was prepared, which proved to be 
of a pale buff colour and possessed some of the charac- 
teristics of oil meals. Consignments of Hevea seed and 
meal were sent by the authorities in Malaya to the 
Imperial Institute, for the samples to be tested and 
reported upon by the Scientific and Technical Depart- 
ment, and the results published in the journal. 
The kernels constitiite about 50 per cent by weight of 
the whole seeds. On extraction with light petroleum 
they yielded 42'3 per cent, of oil (specimen A), whilst 
the whole seed (husk and kernel ground together), fur- 
nished 20 per cent of oil (specimen B). 
HEVEA SEED OIL. 
The oil obtained from the kernels alone is clear, of a 
light yellow colour, and has an odour somewhat re- 
sembling that of linseed oil. It belongs to the class of 
drying oils, and yields a clear, transparent film when 
allowed to dry by exposure to air. The husks contain 
a solid fat, which has a high saponification number 
and a low iodine value, but since the amount of this 
solid fat in the husks is very small, it makes but little 
difference to the properties of the oil obtained from 
kernel and husks ground together. The following 
table gives the constants found for both specimens of 
the oil. those of linseed oil being added for com- 
parison ; — 
Para Rubber Para Rubber 
Seed Oil. A. Seed Oil. B. Linseed 
(from kernels (from whole Oil. 
only). seed). 
Specific gravity 
at 150 c. 0-9302 0-9316 0-931— 0-937 
Free fatty acids- 
Acid value 10-7 19-0 0-8— 8-9 
Calculated as 
oleic acid 5-4 p. c, 9 6 p,c. 0-4— 5-7 p. 0. 
Ester value .. 195 4 19U-3 — 
Neutral oil .. 94-6 p. c. 90 4 p. c, 95-5— 99-6 p.o. 
Saponification 
value ... 2n6-l 209-3 187—195 
Iodine value 128-3 121-2 160—181 
HEVEA SOAP." 
On saponification with caustic soda, the oil furnished 
a rather soft soap of yellowish colour. It was found 
that the time required for the complete saponification 
of this oil is about half as much again as that required 
in the case of olive oil. 
PAKA RUBBEE seed MEAL. 
The sample consisted of about 7 lb. of finely ground 
meal of a pale buff colour ; it was free from husk, and 
possessed the pleasant odour characteristic of oil meals 
On extraction with light petroleum, the meal yielded 
36 1 per cent, of an oil which tiad a slightly acid odour, 
■ and, on standing, solidified as a soft, crystalline, yellow 
mass. It furnished the following constants ; — 
Specific gravity at 15 ° C 0-911 
(Acid value ., ISO'S 
Free acids (calcu- 
lated as oleic 
^ acid) ,. .. 65 6 percent. 
Neutral oil .. .. 34-4 do 
Ester value .. ,. 65-2 
Saponification value 195-7 
Iodine value 136 2 
When heated, the oil began to melt at 19 deg. C, and 
was a clear liquid at 28 deg. C. It had very marked 
drying properties, and yielded a solid, transparent tilmj 
PBOPEETIES OF THE OIL. 
In the following table the constants and properties 
of the oil extracted from this sample of meal are con- 
trasted with those of the oil obtained from the freshly, 
crushed decorticated seeds ; the constauta of linseecl 
oil are again added for comparison, 
