268 [October, 1902.] 
IMPERIAL INSTITUTE JOURNAL. 
Vol. VII L No. 94. 
which, if they could be adopted, would greatly economise the present cost of production. 
The fruit from which the oil is made consists of an outer coating of tough pulp, and an inner 
hard shell enclosing the kernel. The pulp which contains the palm oil is, by the native 
method, first softened by boiling for two hours in water, and then beaten from the hard inside 
shell with wooden pestles, forming a fibrous, oily mass, from which the crude oil is pressed 
out by hand. This raw product is then refined by melting it in hot water and skimming off 
the oil as it floats to the surface. It is obvious that the fibrous residue of pulp must, under 
these conditions, retain much oil, and in one experiment, made under Dr. Preuss’ directions, 
only about 33 per cent, of the available oil was obtained. Usually, however, better results 
are secured, since analyses of the fibrous residue made in Europe show a content of oil varying 
from 12 to 20 per cent. The author gives in the original paper impressive figures showing the 
enormous losses which this failure to extract the whole, -or at least the greater part of the 
available oil, means to West Africa in general and the Cameroons and Togoland in particular. 
At the present time there is no way of avoiding this loss, but he points out that it should be 
possible to devise a cutting machine which would separate tire pulp from the nut, when the 
former could 1 >e readily worked up in some form of hot oil press. A machine for this work 
would, however, have to be capable of readily adjusting itself to deal with fruits of various 
sizes. 
From the mass of pulp referred to in the foregoing paragraph the nuts are picked out by 
hand, and laid aside to be worked up for the contained kernels, the latter being usually ob- 
tained by breaking up the nuts one by one with a hammer, although in a few places machines 
have been introduced for this purpose. The kernels are usually exported as such, no attempt 
being made by the natives to prepare palm-kernel oil for export. The latter is somewhat 
like cocoa-nut oil in properties, and is principally used for the manufacture of soap in Europe. 
Dr. Preuss also gives some interesting information regarding two local varieties of this tree, 
which have been named the small- and large-fruited Lisombe respectively, and which both differ 
from the ordinary oil-palm in having more brittle shells enclosing their kernels ; a peculiarity 
of obvious advantage to the kernel extractor. The following table shows the oil and kernel 
content, and other facts of commercial importance with regard to these varieties : — 
Variety. 
Pulp 
in whole 
fruit. 
Palm 
Oil 
in whole 
fruit. 
Palm Oil 
contained in 
pulp. 
Kernel 
in whole 
fruit. 
Palm- 
kernel 
Oil 
in whole 
fruit. 
Oil 
contained 
in kernel. 
Per cent. 
Per cent. 
Per cent. 
Per cent. 
Percent. 
Per cent. 
Small-fruited Lisombe . 
71 *o 
32*6 
45*9 
9*54 
4*9 
49*2 
Large-fruited Lisombe, ripe 
71*0 
44*4 
62*5 
12*5 
6*15 
50*1 
Large-fruited Lisombe, unripe 
64*5 
40*8 
62*4 
17*2 
8*5 
50*1 
Ordinary Palm . 
37*5 
22*6 
60 *2 
14*5 
7 *i 3 
49 *i 
An examination of these figures will show that the fruits of both Lisombe varieties are 
richer in palm oil than Lhatof the ordinary palm, although they furnish a smaller proportion of 
kernel. Since, however, the latter is less valuable than palm oil, this is no disadvantage. Of 
the two Lisombe varieties it would be best to utilize the large-fruited kind, since this gives both 
more oil and more kernel than the small-fruited sort. The author calculates that aL present 
rates the value of the products obtained from 100 kilos. (225 lb.) of the Lisombe fruits would be 
2 is. gd., whilst the corresponding value of the same weight of ordinary palm fruits would be 
14s. 6d. A series of tables showing the probable profits derivable from this industry is 
given, but it is pointed out that the outlay of capital by Europeans in this direction would be 
unwise until machinery for the extraction of the palm oil has been devised, and as far as the 
Cameroons are concerned, until a railway and good roads have been provided, so that the 
regular transport of fruits to the factories could be ensured. 
FURTHER OBSERVATIONS ON THE MOSQUITO BLIGHT OF TEA. 
In a previous number of this JOURNAL (August, 1901) a short summary was given of a 
report by Mr. Ernest Green on Helopeltis Antonii , the “Mosquito Blight” of tea. The 
following is taken from a paper by the same author (issued as a Circular of the Royal 
Botanic Gardens, Ceylon), and briefly summarises the results of further observations cn this 
subject. 
The present investigation was undertaken in the Kelani valley district of Ceylon, at 
a time when the ravages of this insect pest had considerably abated, although the tea 
plants still showed signs of the recent attack. 
1 he application of an acetylene gas light, as a means of capturing the insect, was tried 
in the following manner. An acetylene lamp fitted with a 50 candle-power burner was placed 
in a vessel containing kerosene and water, and set up in a place that bore ample evidence of 
the presence of Helopeltis. The lamp was lighted soon after sunset and allowed to remain 
until the next morning. The surface of the liquid in the vessel was then found covered with 
a mass of dead insects which, however, did not include a single specimen of Helopeltis. It 
seems evident, therefore, that this insect is not responsive to attraction by light. 
An exhaustive examination of several tea plants was made to ascertain whether eggs 
were being deposited, and in what positions. The result showed that few eggs were 
then being laid, and that of these the larger proportion were in such a position that 
they would be left untouched by plucking the initial leaf. The paucity of recently 
deposited eggs was the more remarkable when it was found that the insects captured at this time 
contained a larger number of fully formed eggs than had been found previously at a period of 
greater activity of the insect. The author concludes from these observations that the period 
of inactivity is marked by the retention of the eggs in the bodies of the insects, until con- 
ditions are more favourable for breeding. The vitality of eggs in prunings was tested, and it 
was found that little danger need be apprehended from hatching of eggs on pruned branches. 
The practical immunity of the indigenous varieties of tea to attack from this pest was 
established, although it is quite possible that the insect may gradually adapt itself to live on 
indigenous tea if allowed to increase sufficiently. 
The ravage caused by Helopeltis is increasing in Ceylon. Estates in the neighbourhood 
of Nawalapitiya at an elevation of about 2,000 feet are becoming affected, and the pest seems 
likely to become as virulent here as at lower elevations. In the Morawak Korale district, as 
in the Kelani valley, it is noticeable that the first period of activity of Helopeltis occurs in 
the dry, hot season, while the recrudescence is coincident with continuous south-west rains. 
Ihe breeding habit of the insect varies at different periods, and it is, therefore, important 
that the quantity of the eggs laid, and the position in which they are deposited, should be 
determined for every month of the year. It may then be possible to arrange a scheme of 
plucking the tea plant to suit the varying habits of the insect. It is recommended that close 
plucking be abandoned, for this system tends to produce a brush-like growth of small shoots 
which are particularly suited to the tastes of the Helopeltis. 
1 he flight of the insect is weak and, as it does not fly high, there is little doubt that the 
work of checking this and other insect pests of similar habit, would be greatly facilitated by 
dividing the estates into smaller areas of from 10 to 20 acres, by growing suitable trees to 
form narrow but compact boundaries. It would be necessary to have some thick undergrowth 
to complete the screen, and for this purpose croton oil, annatto, castor oil or tapioca 
plants would prove useful, for the higher trees Para rubber, coconut, nutmeg or kola- 
nut might be employed. As an alternative the screens might consist of trees and plants the 
clippings of which would prove useful for green manure, such as AlHzzia mohtccana or 
“ Dadap,” with Crotalaria as an undergrowth. 
The results of the present investigation show that more work is necessary before an 
adequate knowledge of tire pest can be acquired, and a complete scheme of treatment 
devised. 
Further investigations are now being made to ascertain the distribution of the pest and 
the extent to which it varies in habit in different localities. 
RUBBER AND GUTTA-PERCHA IN NEW GUINEA. 
Attention has already been directed in this Journal to the valuable information acquired 
by the various scientific expeditions sent by the German Colonial Society to study the natural 
products of the German colonies and dependencies. At the present time a botanist, 
1 lerr Schlechter, has been deputed by this body to visit the South Sea colonies and to collect 
especially samples of rubber and gutta-percha there, for submission to consumers of these 
products in Germany. A report on some specimens so obtained in New Guinea is printed 
in the August number of Her Tropenpiflamer , from which source the following notes have 
been compiled. In March, 1901, several eight-year-old plants of Ficus clastica were tapped 
by incisions made every morning for six days, the exuded caoutchouc being collected every 
afternoon. The yield per tree was about five pounds. In the same month a six-year-old 
Casiilloa species was tapped by felling and “ringing,” the yield in this case being, however, 
only about twelve ounces, and similarly another tree of this species, three years old, gave only 
a quarter of an ounce when tapped by incision. On the other hand, a four-year-old plant of 
Ilevea brasiliensis which was tapped by Curtis’ method for ten days, gave nearly two ounces 
of rubber. The results of analysis of these specimens, made in the Pharmaceutical laboratory 
of Berlin University, and the values assigned to them by brokers and rubber dealers in 
various parts of Germany, are given in the following table : — 
Source of specimen. 
Age of tree. 
Yield, 
02. 
Quality. 
Content of V-duc 
true Caoutchouc, ^ 
per cent. 1 
Ficus elastica 
... eight years .. 
,. So ... 
“ middling ” 
... So*7 2/2 to 2 9 
Casiilloa species 
... six years 
. 12 ... 
“similar to Peruvian 
scrap” ... S4*o 2 4 
Casiilloa species 
... three years ., 
1 
4... 
“ resinous ” 
... 58*6 i/S 
Hevea brasiliensis 
... four years .. 
. 2 ... 
“good” . 
... 90*2 3/2 
A sample of gutta-percha, also collected in New Guinea, was submitted to dealers irt 
this product, and was also analysed in the Berlin University laboratory, with the results 
recorded below. The source of the sample is not stated. 
Content of true Gutta-percha, Content of Resin, v , ,, 
per cent. per cent. a L e ' 
56 to 74*8 25 to 35 2/8 to 4/0 
The variation shown in these analytical results is probably to be ascribed partly to the 
difficulty of securing, with such a substance as gutta-percha, a thoroughly representative sample, 
and partly to the different processes used by the chemists of the various firms to whom the 
specimen was submitted. 
GENERAL NOTES. 
A NEW ELECTRIC FUSE. 
A new form of electric fuse, notable on account of its simple and ingenious construction, 
has been designed by Mr. G. W. Partridge, the chief engineer of the London Electric Supply 
Corporation, and was shown at the recent Tramways Exhibition at the Agricultural Ilall. 
It is chiefly intended for use on high-tension circuits carrying heavy currents, where the 
blowing of a fuse results in the formation of an arc which hitherto has been prevented from 
burning by using a very long fuse or by some form of oil fuse. Thus, on the 10,000-volt 
mains and transformers of the London Electric Supply Corporation, fuses of the tubular 
type, 4 feet 6 inches in length, were employed previous to the introduction of the present 
fuse. In the latter the extinction of the arc is brought about by a jet of carbon dioxide gas, 
which is liberated by the heat of the arc from a “sparklet,” such as is now largely used for 
the production of aerated water. The “sparklet” consists simply of a small steel bottle 
containing liquid carbon dioxide and closed by a cap which can resist a pressure of 600 lb. 
per square inch. Only a short length of fuse wire is employed, and tine terminals of this 
are connected to two sparklets, one at each end, between which the arc forms when the fuse 
is blown. In a very few seconds one or other of these is burnt through and the rush of 
gaseous carbon dioxide immediately extinguishes the arc. In addition to the fire- 
extinguishing properties of the gas there is a considerable reduction of temperature, as the 
liquid carbon dioxide passes into the gaseous state, and the explosion which occurs when the 
sparklet is pierced acts as a very efficient blow-out. Two sparklets are used on each fuse 
for additional security, but in the numerous practical tests which have been made one of 
these has always sufficed, and it is stated that not a single defective sparklet has been found. 
The length of fuse employed on a io,ooo-volt circuit is only 9 inches, instead of the 
4 feet 6 inches fuses which were previously used ; and, in fact, experiments have shown that 
on such circuits the arc can be extinguished with certainty, even when the gap is but half an 
inch in length. At the Agricultural Flail the fuse was shown working on a circuit of 
2,500 volts, and in this case the arc was put out in less than three seconds. The fuse 
operates successfully whether blown by a short circuit or by a long-sustained excessive 
load, the latter being a particularly severe test, as the arc formed in such a case is peculiarly 
persistent. Various types of fuse have been designed for special purposes, and the device 
has also been adapted to switches which carry heavy currents. In these the sparklet is so 
placed that it is ruptured by the arc formed on opening the switch, while a fresh sparklet is 
inserted from a magazine of the revolver type every time the switch is closed. The different 
types of the new fuse have proved most satisfactory in practical use during the last eighteen 
months, and their simplicity and efficiency will commend them for trial to all who have to 
deal with high-tension circuits. 
COCA CULTIVATION IN THE CAMEROONS. 
Among other medicinal plants now being experimentally cultivated in the Cameroons is 
Erythroxylon Coca , the leaves of which yield the valuable alkaloid cocaine. The supply of 
the latter is at present furnished almost entirely by the countries on the Pacific border of 
South America, although several other tropical countries have at various times produced 
small quantities of the drug. The plant is being grown in the Victoria botanical garden of 
the Cameroons, and, according to Her Tropenpjlamer , August, 1902, a small sample of raw 
cocaine has been received in Germany, prepared from the African plants by Squibb’s 
method. The yield of this crude alkaloid was about 8 per cent. A firm of alkaloid makers 
lowborn the sample was submitted asked for a supply of the air-dried coca leaves. The 
latter were collected from the bushes in a small experimental plantation at Bula, and proved 
on examination to contain only ’28 per cent, of total alkaloid. This low result is attributed 
by the chemist of the firm to improper drying, but the editors of Her Tropenpjlanser suggest 
that it may be due to the slight difference in the locality of the two plantations or to 
deterioration of the leaves during the long voyage, and point out that it would be advisable 
to extract the alkaloid in a crude form for exportation rather than attempt to export the 
leaves, unless the latter can be carefully packed in air-tight boxes without unduly increasing 
their cost. 
