n 4 
THE TROPICAL AGRICULTURIST. 
[July i, i88i» 
COFFEE OIL. 
We give the following translation from the Indische 
Mercuur for March :— Although we make daily use of 
coffee as a drink we are not yet fully acquainted 
with the chemical nature and the composition of the 
products which result from the roasting or burning 
of it, nor with the oil, which constitutes one of the 
most interesting and characteristic elements of the 
bean. The presence of coffee oil is completely mani- 
fested by roasting, when the oil, driven out of the 
bean by the power of the heat, is thereby partially 
liquefied, and diffuses, together with other products 
of the combustion, the peculiar aroma of burnt coffee, 
an odour not possessed by any other substance. In 
very strongly made coffee"' the oil can also be seen 
floating in little drops of fat on the liquid. The 
amount of oil present in coffee beans varies from 8 
to 13 per cent, and at least half of this is lost in the 
roasting. It, should be a not unprofitable experiment 
to try to collect this oil, especially in large establish- 
ments, where large quantities of coffee are roasted, 
and thus also large quantities of oil are lost. In the 
year 1871 not less than five hundred thousand tons 
of coffee were consumed, the amount of oil lost from 
which may now be easily calculated. Dr. Cech of St.' 
Petersburg tried the experiment ©f collecting the oil 
in one of the coffee-roasting establishments in Berlin ; 
he connected the machine in which the coffee beans 
were roasted with a sort of condensor and a receiver, so 
that he first cooled the ethereal oil and then collected it 
as a liquid. At the commencement there was scarcely 
any vapor to be collected any-where in the machine, but 
when the beans became brown and the whole m ass was 
well heated such a large quantity of ethereal oil was pro- 
duced that it could be collected after condensationin tbe 
form of successive drops. If this operation is performed 
in a chamber, without making use of such a condensor, 
the oil runs in little streams along the cold walls. The 
requirements of roasting have hitherto been of such a 
nature that the roasting and stirring take place in the 
open atmosphere, which makes the condensing and 
collecting impossible. Experiment has taught however 
that the coffee which is being roasted must, as soon as 
thebeans are brown, be brought away from the heat to 
be stirred, as it is feaied the mass would be burnt if this 
were not done. Andthat is just the moment when the 
oil is being most largely produced. If any one could 
think of a method of uniting the spit with an exhauster, 
which would collect the gases and convey them to the 
condensor, and which wouldon the other hand admit 
sufficient air to cool the beans completely, he would 
be on the road to success. Dr. Cech is of opinion that 
the oil extracted is admirably adapted for the manu- 
facture of liqueurs. In order to study the properties 
of coffee oil Dr. Cech pounded 50 lb. of different 
kind; of coffee to powder in a mortar, than made a 
decoction of it with alcohol and ether, and so obtained 
two and a half lb. of extract. The beans used were 
not all of the same good quality : some sorts had 8 
others 13 per cent of oil, indeed there were some that 
had less than 8 per cent oil. The coffee oil is green, 
thick, and transparent, and after it has stood for some 
time fine long needle-shaped crystals are deposited. 
These appear to be caffeine. This oil becomes turbid in 
the space of half a year, though it may have been kept 
in opaque stoppered flasks. In the course of time more 
and more crystals are deposited, and after about a year 
the flasR ts half filled with a dirty colored mass of 
crystals ; the liquid floating above however appears 
transparent, clear, and of a fine green color, from 
which it is to be inferred that a portion of the cof- 
fee oil consists of a fluid oleaginous acid. The per- 
centage of composition of the coffee oil is however so 
far not yet ascertained. This still needs the attention 
of practical chemistry. Time mu9t teach what can 
yet be made with the oil. 
CINCHONA CULTIVATION . 
Dr. Trimew on Red Bark. 
Mr. Eliot Howard Extinguishing "C. Pubescens 
How." 
We draw special attention to Dr. Trimen's letter 
giving a full explanation of his views in reference to 
the culti vation of red bark. It seems that the Director 
in deprecating the extension of cultivation with the 
inferior sorts, referred to the Calisaya species only 
and not as we supposed to Succirubra. In addition 
to the reasons now given for regarding the red l ark 
with favour, we may mention the fact that it is used 
in the manufacture of Ix-er in Germany, and the prob- 
ability that through the shaving process, the renewed 
produce may prove to be a manufacturer's bark ot 
no mean value. Crown bark in all its degrees requires 
no advocacy, and of course the fortunate possessors 
of Ledgerianas and the finer Calisayas are to be envied 
rather than treated to words of encouragement ; but 
we would fain put in a good word even for the 
"inferior" Calisayas in so far as to deprecate dis- 
couragement after the very satisfactory analytical and 
market results obtained by Mr. J. A. Roberts of 
Pussellawa and the proprietor.? of Emelina. It seems- 
probable that in the Ceylon climate and soil C. Hass- 
karliana, Josephiana, &c, will, for some reason oi 
other, give better results than in Java. At any rate, 
the trial ought to he persevered in by those who have 
already planted these kinds, while in all future clear- 
ings, planters should as far as possible aim at putting 
out the best, taking elevation, climate and soil into 
account as well as the plants available. Where C. 
officinalis succeeds well in Ceylon, it may be a ques- 
tion if a more profitable kind can be planted taking 
everything into account. We suppose the finest and 
most promising cinchona clearings of this kind to be 
seen at the present time in the island are between 
Udapussellawa and Nuwara Eliya in the Kandapola 
division, at elevations of from 5,500 to fully 6,000 
feet. Nothing can exceed the regularity and vigour 
with which crown bark trees flourish in this region, 
and it will be interesting by-and-bye to compare the 
yield of bark and prices obtained for the same, with 
those realized for the Ledgeriana trees grown in Ceylon. 
Our correspondents "T. N. C," " W. F. L," " T. 
C. O.," and other cultivators of cinchona will be in- 
terested in the letter which has just reached us from 
Mr. J. Eliot Howard. Our readers will remember the 
discussion which took place /in our columns over the 
different varieties of Officinalis and on the value and 
position of certain hybrids. " C. pubescens, Howard " 
was freely referred to as one of the best recognized 
hybrids between C. Officinalis and Succirubra, and Mr. 
Clements Markham's mistake in putting it as a hybrid 
of Calisaya and Officinalis was commented on. We 
think " T. N. C." stood alone on that occasion in his 
wish to drop the name " C. Pubescens " as mislead- 
ing for the hybrid, but here we have Mr. Howard 
himself asking that the coup-de- grace may be given to 
the variety associated with his name, the term " C. 
pubescens " being used for a species long ago estab- 
lished and having quite different characters. Mr. 
Clement, Markbam will have to correct his book. Mr- 
Howard writes as follows :— 
Lord's Meade, April 29th, 1881. 
Dear Me. Ferguson.— I have to thank you much 
for a copy of your Hand-Book for Ceylon just received. 
I find that I am credited with having created a new 
species of Cinchona, the " C. pubescens How.''' I do 
not say that I find this in your book ; for I have not 
had time to examine it; but my correspondents in 
Ceylon are writing to me about it. I think I have 
pointed out before that this is all an error, arising from 
my suggesting to Mr. Mclvor the word pubescens as 
applicable to one out of two hybrids, found by hint. 
