536 
THE TROPICAL AGRICULTURIST. [December i, 1881 
is an important onee preparatory to passing the sugars 
through the charcoal filters. To watch this process we 
have to perform certain gymnastic feats which require 
extraordinary care, unless the acrobat wishes a bath in 
boiling water. The liquor, still of a dark hue, is ran 
to another cistern, whence it is pumped into large cast 
metal receivers, which in turn feed the charcoal filters. 
The passage of the sugar through these is the part of 
the system which has most interest and novelty to the 
untravelled colonist. The charcoal filters are huge tanks 
of cylindrical form, and are composed of cast iron plates. 
They are about seventeen feet deep and over five feet 
in diameter, and they are furnished with a perforated 
false bottom placed about three inches above the real 
one, its removal permitting of thorough cleansing. The 
true base is of a conical shape, which allows all the 
liquor passing through the charcoal to be collected at 
one point in the centre, and so be drawn off to the very 
dregs. The cistern is permanently closed on the top, 
although there is at the bottom a man-hole door to 
permit the charcoal being withdrawn. The filters con- 
tain about five tons of the charcoal through which the 
melted sugar passes in precisely the same way as water 
is sometimes filtered through sand. The bone charcoal, 
in . order to its continuous use, of course requires great 
nicety and cleanliness of treatment. In the meantime 
the charcoal is imported, but we expect to see it manu- 
factured on the spot soon. It must be washed thoroughly, 
otherwise it would get impregnated with oxide of iron, 
carbonate of lime and other substances which would, of 
course, have a deleterious effect on the sugar, making it 
lose both its colour and weight. The material — which, 
to the superficial observer, has the appearance of fine coal 
" dross " — is therefore removed from the filter, washed 
with hot water for some hours, after which it gets a 
sousing for four hours in cold water. The charcoal on 
being taken out of the filter is run up by an ingenious 
hoist to the top of the kiln, where it goes through the 
process of being returned and revivified. This kiln is 
composed of thirty pipes equally divided on each side 
of the fire, and these pipes are kept constantly at a good 
heat. The charcoal passes through them, and is received 
into coolers without coming into contact with the ah-. 
These coolers are divided into two parts, and from the 
under part a charge of charcoal is drawn every twenty 
minutes, thereby allowing only the same quantity to be 
put into the pipes at the top. It will be seen, there- 
fore, that the kiln is so regulated that the operator, 
who is generally not a skilled man, cannot draw off 
more than a certain quantity of charcoal at a time. 
Having watched how the charcoal is dealt with and 
made fit for its valuable purpose, let us return to where 
we saw the sugar pumped from the cast metal receivers 
to go through the niters. It is led by pipes from the 
bottom to a small square box, where the liquid is divided 
and rim into receivers, whence it is drawn to the vacuum 
pan as the operator requires. To sum up then : — The 
concrete is melted and passed through the bag-filter to 
extract extraneous matter — a merely mechanical process. 
It then passes through the charcoal — a chemical pro- 
cess — to decolorise. The concrete is now liquified, and 
its turn has come to be made into respectable sugar. 
It is therefore taken back to the vacuum pan, to have 
the water which we have seen put into it taken out, 
and thus to have it crystallised. From the vacuum pan 
it goes straight to the centrifugals, the syrup being 
sent back to go through the process we have described, 
as very little syrup is put out at the Abergeni Sugar 
Works. We harve now seen the huge lumps of dirty 
concrete, with all its impurities, sent through the mill 
and returning to bags waiting for it as perfectly clean, 
wholesome sugar. It only remains to be said that the 
boiling department is under the competent charge of 
Mr. Ileinis, and that the manager of the mill is Mr. 
T. II. Wilson, who has had sixteen years' experience 
of bis business on the Clyde. So far the results ob- 
tained at the works have been highly satisfactory ; and 
when a new kiln, now on the way out, is erected, the 
output will probably double itself. We wish Mr. Wil- 
heim every success in his praiseworthy enterprise. — Natal 
Mercwry. 
CINCHONA :— RED BARKS. 
(Pharmaceutical Journal, 3rd September, 1881.) 
In a paper on " Red Bark," read before the British 
Pharmaceutical Conference, Mr. John Eliot Howard 
adopted the distinction made by Professor Karsten be- 
tween the genera Cinchona and Cincinchona, namely 
that in the former the capsules are dehiscent from the 
apex and in the latter from the base, and described 
what was to be understood by the term " red bark. " 
Cinchona succirubra, the true species of the red bark, was 
so named by Pavon to denote the peculiarities of the juice. 
Like other species, it exists under somewhat different 
forms (illustrated by specimens that were exhibited) and 
the differences, though apparently trivial, are important 
to the cultivator for reasons that have been explained 
in the 'Nueva Quinologia,' and on account of the relative 
preponderance of quinine or cinchonine and cinchonidine. 
Specimens of genuine red bark and of the more resinous 
sort which used to be imported from South America and 
sold at a high price, though useless to the quinine 
manufacturer, were exhibited to illustrate the state of 
degeneration to which Mr. Howard predicts that the 
truest red bark in India will arrive by age, and towards 
which Mr. Broughton believed some advance was made 
during the continuance of his observations. Since that 
time Mr. Howard has had the opportunity of examining 
specimens of much more mature bark carefully collected 
by Mr. Cross at Ootacamund, and exhibiting the true 
characteristics of genuine red bark. These samples con- 
tained respectively 0-86 and 0 91 per cent, of quinine, 
with 1-5 to 2-0 per cent, of cinchonidine, and 3-5 to 
4 - 0 per cent, of cinchonine. In reporting upon these 
barks to the Marquis of Harrington, Mr. Howard pointed 
out that they are most characteristic specimens, well 
illustrating the mistake of the excessive cultiuation of 
C. succirubra, and that it is only by renewing that the 
bark of such trees can be made serviceable. Another 
sample described as red bark is not from C. succirubra, 
but is the produce of a tree yielding juice that becomes 
only golden coloured, and identified by Cross as " Pata 
de Gallinazo." That it is a much better sort for culti- 
vation than the C. succirubra, with which it has been 
confounded, is shown by its containing 2-25 per cent, 
of quinine. The fidl information upon both these barks, 
which was published by Mr. Howard and sent out by 
the Government in 1862, has apparently been without 
result, as these two species are still confounded under 
the name C. succirubra. There is also a third species 
confounded under this head, the " cucharia," or " pig, 
skin," a sort of red bark, little valued formerly by reason 
of its poor appearance ; but in regard to contents in 
alkaloid more valuable than the true red bark, as it con- 
tains from. 1-37 to 2-14 per cent, of quinine. The pro- 
pagation of so many millions of trees of what is called 
C. succirubra in India, in spite of the warnings and of 
the information gathered from the Spanish botanists; 
strongly impresses Mr. Howard with the question whether 
the information he is now giving or may be able to 
render hereafter, will be turned to any account, other- 
wise than amongst those private cultivators who gladly 
avail themselves of such assistance, and who will find 
eventually that they have done well to attend to the 
careful discrimination of species and forms of species by 
cultivating oidy those most adapted to then purpose. 
A paper by Mr. Holmes, raising the question which 
kinds of cinchona bark should be used in pharmacy, 
pointed out that the kinds of barks now cultivated in 
Java, India, Ceylon and Jamaica, have been former years 
a regular article of commerce, but are not recognized 
in the pharmacopoeias, and cannot therefore be used for- 
