142 
Supplemmt to the “ Tropical Agriculturist'' 
[Aug, 2, 1897. 
tliouglit over the possibilities of stiirmlatiiig the 
native agriculture of the Island. AV^e have our- 
selves made similar I'ecommendations off and on, 
but in this country it is necessary to have an accu- 
mulated mass of corroborate opinion gathering to 
a head before one can hope to roll away the obsta- 
cles which those whose policy should be to promote 
the pros])erity of the indigenous population by 
the adoption of all reasonable and tried measures, 
are ever ready to jdace in the way of advance- 
ment and refcrm. 
WOOD ASHES. 
The use of wood ashes for manurial purposes 
dates from a very remote period, and the chief if 
not the only object held in view by its use as such 
is to supply the potash required by plants. AVhether 
wood ashes fulfil this requirement is another 
question, with which we are at present not con- 
cerned. 
'J’o some e.vtent the composition of the ash of 
wood varies according to the sources from which 
the wood has been obtained, that is to say accord- 
ing to the kind of plants from which the wood has 
been got. It also varies according to the parts of 
trees used, for instance, as Warrington points out 
in his Chemistry of the Farm, the ash of young 
boughs is 1 idler than that from full-sized timber. 
In rural distiicts where twigs instead of split wood 
are the chief kind of fuel used, we would expect to 
find a rich ash. In this connection we might also 
refer to the common use of the leaves, shells and 
husks of the coconut for burning, whereby a form 
of ashes that can hardly be characterised as “ wood 
ashes ” is produced. Dr. Falconer lung, the City 
Analyst of Edinburgh, gives the following ratios 
representing the quantity of ash from different parts 
of jilants ; taking wood ns 1, the ratio forotherparts 
are, seeds 3, stem and straw 5, roots and tubers 7, 
bark 7 and leaf 13. As regards the composition of 
woodashes,outof seventeen samples analysed atthe 
Connecticut Experimental Station last year, the in- 
gredients varied from 2 to 7 per cent of potash, 1^ 
to 2 per cent of phosphoric acid, with an average 
composition of potash 5 per cent, phosphoric acid 
Ij.lime^G.sand and soil 15, and charcoal 2 per cent. 
But the value of wood ashes varies most 
according to the condition in which it is obtained, 
that is, according to the treatment which it has 
under gone after it, has been produced. It is a com- 
mon experience to find ashes left exposed to the 
sun and rain which help to materially lower its 
value as a potash manure. It has been found by 
analysis that while the potash in “ unleached ” 
wood ashes varies from 2 to 8 per cent, that in 
“ leached wood ashes varies from 1 to 2 per cent 
only. Leaching or letching is the process by 
which water is made to pass through wood 
tishes, in order to separate the alkali in the pro- 
duction of lye. Now' this is just what often goes 
on when ashes are left exposed to our tropical 
rains, the result of which would tend to 
justify the advice wh.ich we read in an American 
Exchange, viz., “Wood ashes should be produced 
on the land and should never be bought, as the 
piico or the potash contained in them is, as a 
rule, far too high to justify their purchase.’’ AVe 
Would remark, however, that this applies to a 
country where 45s. is asked for a ton of wood 
ashes. But where the stuff could be got at about 
half the cost, and where, moreover, it is pos- 
sible to insist on the ashes being prrotected against 
sun and rain, the advice giv'en above is not 
altogether justifiable. 
TheConnecticutExperiment.'iLStation has arrived 
to the conclusion that in addition to the value of 
W'ood ashes as a fertilizer, they must also be re- 
garded as a source of lime inthe form of carbonate, 
and is inclined to attribute their admirable effect 
on many soils to the lime quite as much as to the 
other elements contained in it. 
In view of the importance attached to potash 
manures in scientific circle.--, as the result of 
careful experiment to estimate its value as 
a fertilizing agent (vide articles on “I’ctushand 
Potash Manures” in the Alagazine), all tropical 
cultivators would do well to conserve, and obtain 
wood ashes from every available source for appli- 
cation to their land in conjunction with their 
nitrogenous and phosphatic manures. 
♦ - 
FEU IT CULTURE. 
( Continued.) 
RE*^piaATioN OF Active Hoots dependent on 
THE Mechanical Condition of the Soil. 
It cannot be too strongly impiressed upon the 
cultivator that the roots of trees are not passive 
occupiers of the ground, but have vital functions 
to perform which require the soil to be presented 
to them in a suitable mechanical condition. They 
have to respire. If the soil around them be so 
compact as to exclude air. or if it be drenched 
with water so as to drive the air out of its inter- 
stices and keep it out, the roots -will infallibly die. 
In fact they can no more do without the small 
quantity of air they need than animals can do 
without the enormous suppilies necessary for their 
more active respiration. The difference is one of 
degree only. The respiratory process is the same, 
consisting in the intake of atmospheric oxygen, 
its use to oxidize carbon comxiounds, and the sub- 
.sequent output of carbonic acid. But because 
vegetable respiration, even from the leaves, is 
vt-ry sluggish, and masked from observation by the 
much more active work of assimilating carbon to 
build up ihe tissues, it is apt to be overlooked. 
And from this ignoring of a vital necessity spring 
some of the worst errors in cultural practice. We 
have enumerated certain mineral soil-contituents 
which must be present amidst the vast bulk of 
earth the planter has to deal with. It follows 
from the above that besides these, and in fur 
greater bulk, there must be present afr and tuater. 
The only way in which these two elements, a gas 
and a fluid, can be secured for the service of the 
roots is by breaking up the soil into a more or less 
powdery, porous, open condition by mechanical 
means. In the interstices of the separated parti- 
cles of earth there enters an abundant modicum of 
air, nearly equal in cubic measurement to the bulk 
of the solid matter of the soil. One may almost 
predict the degree of success of any cioj) by the 
degree to which atmospheric air has been mixed 
up with the earth it is to grow in. The traditions 
of agriculture unconsciously point to the same 
