6o 
THE TROPICAL 
AGRICULTURIST 
[July i, 1881 
gardens and the premises where the leaf is prepared, 
and was astonished at the simplicity of all I saw. 
Tea growing is here an experiment, which has, however, 
succeeded very well. It has been proved here that 
i* was not at all necessary, as so many had hitherto 
believed, to proceed to mountains 3,000 or 4,000 feet 
high for the sake of this plant." 
The same journal, in its number of the 24th May, 
comments as follows on the report by a com mission 
on Van Maanen's artificial coffee drying method : — 
"The caution exercised by the Commissioners in their 
final judgment, we do not disapprove of. The results 
obtained in Ceylon from artificial drying of coffee by 
another method makes such a course a duty — but 
we cannot leave unnoticed that the advantages of 
Van Maanen's invention are so great, that the adop- 
tion of the mode of drying will, in many cases, be- 
come advisable, even if it should turn out that the 
color or the quality generally suffer a little from it. 
It ought not to be forgotten that the colour of coffee, 
though certainly of some value, is not so greatly so 
that a saving of 3 or 4 guilders per pical should not 
counterbalance thu damage. The very considerable 
exper.se of constructing and keeping the drying recepta- 
cles in repair, the wages paid to labourers charged 
with the drying of coffee, and, above all, the risk 
attending drying in the open air, are wholly avoided 
by Van Maanen's method. This also furnishes further 
the advantage, that people become wholly independent 
of the height and dampness of the atmosphere, and can 
also send their produce 2 or 3 months earlier to 
market." 
In the official report on the Western Division of 
Borneo for April, it is stated that the Liberian coffee 
plants in the Sintang district looked nourishing and 
had already attained the height of half a ■ metre. 
Their distribution among the people will be proceeded 
with. 
" Padang, 19th May. — A. correspondent writes as 
follows from Bandar, an out post in Palembang :— The 
Dempo or Holy Mountain, which has a height of it 
is said 10,000 feet above sea level, and is inhabited 
by elephants, rhinoceroses, and goats, but which ac- 
cording to the natives is the abiding place of hun- 
dreds of protecting spirits, dewas and other divini- 
ties, is now visited by an Englishman who intends to 
ascend the three summits — Dempo, Lumut and Berapa. 
He has undertaken the journey at a favourable time, 
if he wishes to see something, for the volcano has 
been very active of late. There have been gold dig- 
gings at, the foot of this mountain hut they are now 
of little consecruence."— Sumatra Courant. 
TASSAR SERICULTURE IN INDIA. 
The Secretary of State for India has just communic- 
ated to the Society of Arts a despatch from Major 
G. Coussmaker, dated Camp Rajur, Ti'luka Akola, 
March S, and reporting on the progress made in tassar 
sericulture during the preceding year. He considers 
that his failures last monsoon were due to the imper- 
fect construction of cages in which he tried to rear 
the worms. They were at first made entirely of tarred 
screens of split bamboos, in which, however, the plants 
did not thrive. He then marie the cages longer, and 
covered the tops with netting ; but. unfortunately, 
wasps, &c, managed to get in and puncture the silk- 
worms, so that most of them died. Next monsoon 
he proposes to substitute for netting coarse open cotton 
cloth. The small plantation which has been laid out 
is thriving, and will eventually be able to support a 
considerable number of worms. Major Coussmaker 
had not been able to get all his accounts in, but he 
believes that not more than 220 out of the 500 rupees 
granted him by Government were expended on his 
nteresting experiment. — Pall Mall Budget. 
ARTIFICIAL INDIGO. 
A recent discourse was given at the Royal Institu- 
tution by Professor Roscoe, F. R. S., on "Indigo and 
its Artificial Production." The professor reminded the 
members of the institution that eleven years ago he 
had laid before them an account of a discovery in syn- 
thetic chemistry of high importance, that of the arti- 
ficial production of alizarine — the colouring substance 
of madder. That wa6 the first time the colouring sub- 
stance of a plant had been artificially obtained from 
mineral products. He had now, he said, to give an 
account of a second striking case of synthetic chemistry 
in a similar direction— the artificial production of indigo. 
It was another proof of the fact that the study of the 
most intricate problems of organic chemistry, and tho-e 
which appear to many to be furthest removed from 
any practical application, are in reality capable of 
yielding results having an absolute value measured 
by hundreds of thousands of pounds. The value of indigo 
imported into this country during 1879 amounted to close 
on 2,000,0001 sterling, so that if artificial indigo can 
be produced at a price to compete with natural indigo, 
there is a wide field open to its manufacturers. 
Indigo has I een known as a colouring matter from very 
early times. Cloth dyed with indigo has been found 
in the Egyptian tombs. Pliny and Dioscorides des- 
cribe the method of dying, which is the same as 
that followed in Bengal at the present day. The 
early inhabitants of this island obtained it from the 
European indigo plant isatis tinctoria, the wood plant 
or pastel. After the discovery of the passage to India 
by the Cape of Good Hope, the Eastern indigo, de- 
rived from a species of indigofera, gradually displaced 
woad as containing more colouring matter. This, how- 
ever, was not done without strong opposition from, 
the European Powers and their Sovereigns, some of 
whom issued edicts prohibitory to its importation. The 
identity of the colouring matter of woad and of the 
Bengal plant was not established till the end of the 
last century. Concerning the origin of indigo in leaves, 
various conflicting opinions have been held. -Schunck 
has, however, j>roved beyond all doubt that neither 
in the woad plant, the Indian, nor the Chinese and 
Japanese indigo plant does indigo blue exist as such. 
The leaves contain a colourless principle, which has 
been named mdican, but this readily decomposes into 
(1) a sugar-like body, and (2) indigo-blue. It was 
shown by experiment that even bruising a leaf will 
produce this decomposition ; but to secure the result for 
commercial purposes is a long, though not very compli- 
cated process. Before the synthetic production of indigo, 
could be attempted an exact analysis of the natural 
indigo had to be known, not only as to its molecules, 
but as to the arrangement of the molecules among them 
selves. The synthetic production of indigo had proved 
a far greater puzzle than that of alizarine. The first 
step as to the constitution of indigo was made as far 
back as 1840, when Fritsche showed that analine could 
be obtained from indigo. After some intermediate 
steps, it was found a crystalline body, to which the 
name of isatin was given, was obtainable from indigo, 
and then, in 1878, it was found conversely indigo could 
be obtained from isatin. There are three processes now 
known for obtaining indigo from isatin, but two of 
these are too costly to be of commercial value. Baeyer's 
process seems, however, to be even more than promis- 
ing — to have established itself. He started with cinna- 
mic acid from oil of biiter almonds, but this was too 
costly. Dr. Caro aud Mr. Perkins have discovered how 
to obtain the cinnamic acid from tolvine— a coal-tar 
product. From cinnamic acid, however obtained, can 
be produced an acid complex in character, and to 
which a name descriptive of its composition is given — 
ortho-nitro-phenyl-propiolic acid. The artificial pro- 
duction of indigo may even now be said to be within 
measurable distance for commercial success, for the 
I ortho-nitro-phenyl-propiolic acid (called for short 
