^34^ THE TROPICAL AQRI0ULTURI8T. [August r, 1891. 
maistry would be ample. Ae 10 tons to an acre ia 
under 201b. of mannre a tree it would not be very 
hard work and could be easily done for KIO an acre 
as the total coat of application. Carting can generally 
be avoided, but if it cannot it would not average over 
K2 an acre (less at 10 tons to the acre) as carting could 
■ not be necessary on all fields. As a matter of fact, 
planters apply 20 to 301b to each of 1,742 trees in 
an acre, or 15 to 22 tons, and this can be done for a 
oost of from Ks. 13 to K.17'8 for application, according 
to the distance and lay of land etc. 
It would be a mot desirable state of thiiige if we 
could dispense with bulky maunrea, and depend en- 
tirely on the advise of the chemist as to the use of 
small doses of artificial manures. Bat only the result 
of which planters so far are certain is that if they 
can apply sufficient bulky mannres, such as cittle 
mr»nure or decayed vegetable matter, they can bo 
certain of abundant crops. Evan those who have been 
most snooessful with bone and poonac recognise that 
bulky manure once in three years at least are a 
necessity, althongh largo accumulations of leaf are 
received from the shade-trees which are now a sine 
qua non with coffee. Nor do they believe in small 
doses. £4 of steamed bone dust and £12 of poonac 
every year is a miuimnm doso, and men would apply 
more if they could afford it. This may be abs(jlate 
waste from a chemist's point of view, but it is a 
fact that such over manuring is the only way to 
make coffee pay. Nor is this remarkable when we 
know that over-doses of phosphoric acid improve all 
crops, even these which have only a small proportion 
of that element in them. I do not wish to aeem 
captious. I am exceedingly grateful to Mr. Pringle 
for the information he has given us and would be 
delighted if he would eradicate borer and leaf-disease. 
But we have found so often that the teaching of 
the chemist does not, for some unforeseen reason, 
produce in the field the effect it theoretically should 
produce, that we prefer to go on with our old waste- 
ful ways, — certain that the result will be that if 
we can only apply enough, someUiing or other in 
the old fashioned manures does tell. If is only 
rotten wood, 2 or 3 iriches of it on 6 inches of 
mould, will grow such coffee as no artificial manure 
can. If Mr. Pringla wishes to turn us from onr 
ways let him grow finer fields ou regulation doses 
of artificial manures aao we will believe ; but that 
^•s the only wey. Solvitdb Ambdlando. 
P.S, — Howdoes Mr. Pringle get lucerne, clover, etc., 
to grow under good coffee f I have tried gram (koolty) 
and find it will not grow under any shade. Of course 
it might be grown in young ooffee. 
^ 
THE LEAF DISEASE OF COFFEE. 
Sir,— In your issue of the 30th there is a misprint, 
days being written for weeks in the sentences " When 
the cells are emptied a yellowish spot appears, generally 
visible about two to three weeks (not days) after 
the parent spore is planted." In the next column are 
three errors viz. " the estate was rid of it from end 
to end," should be "the estate was red with it from 
end to end." Lower down "The coolies pick up spores" 
should be " coolies kick up spores," and the word 
"post" for "host." Now in regard to your Ooorg 
correspondent's letter of the 27th re leguminous trees. 
Dalhergia latifolia (Beetle) is given in Vol. 1 of the 
Mysore and Coorg Gazetteer as one ; it is certainly the 
best shade tree in South Ooorg judging by the coffee 
under it. I would auggest that Mr. Oameron of the 
Lai Bagh, and the Manager of the Madras Agri- 
hotticultural Gardens, Mr. Gleefon,be asked to furnish 
a list of the leguminous trees that are not surface 
feeders. Here is an extract which will, I liope, show 
your readers how the question of the fixation of 
nitrogen is being worked at : — " It was first in the 
year 1878 that it was shown by Schloesing and Muntz 
to be dependent upon the presence of certain minute 
forma of life, or micro-organisms, or in other words 
to be a fermentation change;" Quoted from F, and 
G. O. Franklin's "The nitrifying proceafl and its 
epeoifio ferment." The following ia quoted from 
' New experiments on the question of the fixation of 
free nitrogen by Sir J. B. Lawes and Dr. J. H. 
Gilbert": — "Experiments similar to the well-known 
ones of Hellriegel, which were commenced in 1883, 
have been made by the authors at Rothamated in 
1888 and 1889. The results fully confirm Hellriegel's 
statements, and show large gains of nitrogen over 
that contained in seed and manure in many cases of le- 
guminous plants grown in prepared sand or soil contain- 
ing known percentages of nitrogen. The cases showing 
this luxuriant growth and increase in nitrogen were 
those in which the root tubercles were well developed 
and this whs brought about by adding a little aque- 
ous extract of the crushed tubercles to the prepared 
pots, or by watering them with the washings of soil 
in which aimilar leguminous crops, provided with root 
tubercles, had grown. The authors therefore are now 
prepared to endorse the conclusion drawn from Hell- 
riegel's experiments that althongh chlorophyiious 
plants may not directly utilise tbe free nitrogen of 
the air, some of them at any rate may acquire nitro- 
gen brought into combination under the influence of 
lower organisms, the development of which is ap- 
parently, in some cases, a ooinoidont of the growth 
of the higher plant whose nutrition they are to serve." 
There are over a dozen of the cleverest ohtmists of 
Europe and America working steadily experimentally 
at these questions, and every point ia tested by in- 
dependent investigators, keenly critical, as is shown 
by the above extract. Leguminous plants may be 
said to have a parasitic beneficent lower organism 
developed with them, which possesses the power of 
rendering nitrogen capable of beina fixed by the plant. 
Thus it is that they afford a cheap means of obtain- 
ing nitrogen from the air. As regards shade trees 
my experience is that, in South Coorg, all surface 
feeders are bad, and I do not think surfaoe feeding 
leguminous trees would be exception, but they might. 
Only experiments can decide the question. 
William Pringle, M. b, c. r. 
Bangalore, July 2ad. 
. ^ 
COAL IN CEYLON ; ELEPHANT LEATHEE. 
Great interest is felt hero in your announce- 
ment that coal has at length been discovered ia 
Oeylon. If it can ha demoastratsd that the 
material found is absolutely coal, any inferiority of 
quality which may be reported as to the samples 
sent home need have no efieot in disheartening you 
as to the ultimate value of the find. All ex- 
perience has shown that surfaoe ooal is of little 
relative value, and the real quality can never be 
ascertained until a considerable depth has been 
reached. Should preliminary reports justify it, we 
hope to hear that some deep borings have been 
made in order to obtain samples which may 
enable an accurate teat of quality to be established. 
We think that geologists who have visited Ceylon 
hitherto have generally reported adversely as to 
the likelihood of ooal being found in the island 
but these reports have not shaken the faith of 
many who have entertained a confident hope that 
the mineral would be discovered someday or other. 
Having read yuur extract from an American 
paper referring to the use of elephant leather, I 
paid a visit this week to Messrs. Toulmin & Gale 
to learn what they know of the subject. I was 
assured by them that they had never heard of 
elephant leather being employed in the manufacture 
of the articles mentioned in your extract referred 
to. They said a leather was known in their trade 
as " elephant leather," but this was only cowhide 
stamped in imitation of the latter, and they 
expressed their belief that it was impossible to 
work up the genuine thing into bags, pocket-books 
&c. They showed me a piece of elephant hide in 
their possession and asked me if I did not see the 
impracticability of so adapting it. However, they 
obligingly sent for tbe foreman of their wrorks, witl} 
