MANURING COFFEE. 107 
phosphates and potash. Dissolved in water we can by 
their aid prepare from them a sort of artificial urine, 
which if thrown into the manure pit effects the dis- 
integration of the haulm husks and more especially 
the straw itself.” This may afford a useful hint with 
reference to the maturing of composts. But we must 
close this article by giving the very heart of M. Ville’s 
system. ‘‘ The question then is,” he says, ‘‘Can we, 
with chemical manures, cutivaie the same soil with uni- 
_form success? Yes, we can, but always on two con- 
ditions :— 
*‘(1) Return to the soil by the aid of manure more 
calcic phosphate, potash and lime than the crops have 
‘taken out of it. 
“‘(2) Restore to the soil about 50 per cent of the 
mitrogen of thecrops. I say about 50 per cent, because 
there are certain plants which require less, while others, 
leguminous plants for instance, seem to be able to do 
without any nitrogen being returned to the soi]. We 
-have already stated that part of the nitrogen required 
by plaats is derived from the air, while some planis 
‘draw it more particularly from the soil. 
_ ‘With respect to the calcic phosphate, potash and 
ime, the quantity restored must be in excess of that 
which is lost, because it is exclusively from the soil that 
plants draw them, and we must not only give com- 
‘pensation for the losses brought about by eich harvest 
but also for those which are due to the solvent action 
of rain.” 
~The bearing of these principles on coffee and other 
culture is obvious. We have to find out, in the case of 
coffee, what constituents are removed in crop, (parch- 
ment skin as well as clean beans) and no doubt we must 
make allowance to some extent for prunings and 
wandlings, and to a large extent we fear for foliage 
dost by leaf disease. 
190, Kollupitya Road, Dec. 6, 1879. 
DesR Si1r,—The sanguine hope of M. Ville, that ad- 
vanced agriculture will yet be able to draw all the 
nitrogen required for plant food from the atmosphere, 
jends a new interest toa subject touched upon in my 
last, viz., may not the secretof the lessened import- 
amce of the more active forms of nitrogen in our 
ynanures, compared to what obtains in temperate coun- 
tries, be explained on the supposition that our atmo- 
spheric supply of available nitrogen is greater, either 
absolutely or relatively, to the products we have to 
cultivate? I am not awareif any tropical rains, dews, 
~or atmosphere, have been made the subject of exact 
