November i, 1889.] THE TROPICAL AGRICULTURIST. 
355 
very roots." I said and meant nothing more than 
these words imply, and I emphatically protest against 
a meaning contrary to my intention being placed on 
my words. I did not use Liebig's dictum with ap- 
proval, for all I contended and contend for is the 
issue of salt for agricultural purposes at special rates. 
If salt be issued at special rates to the manufacturer — 
the fish curer — it ought a fortiori to be issued on the 
same terms to the producer, the agriculturist. 
True enough, experiments have not established the 
value of salt in coconut cultivation, and why ? Because 
the cost of such experiments will be prohibitive with 
salt at the usual rates. My contention is that no 
risk to the revenue will be incurred by issuing salt 
at special rates for agricultural purposes, under proper 
safeguards and mixed with some objectionable substance 
like night soil. Experiments may have proved the pos- 
sibility of thoroughly purifying such salt, but the probabi- 
lities that such experiments will be carried on to fit it for 
culinary purposes are in the highest degree remote. 
I have not asserted in general terms that salt is 
of special value manurially. All I say is that it has 
a special value in coconut cultivation carried on 
in regions beyond the influence of salt-laden breezes, 
or to be more accurate, that have not the requisite 
quantity of salt in the soil. I base this my belief 
on the results of my observation of the difference in 
the habits of the coconut trees growing on the sea 
borde and in inland districts, especially as regards 
the latter not being able to support their fruit 
branches without extraneous aid, on the results of 
the analyses of every part of the coconut tree, and 
an axiom in agricultural chemistry that plants cannot 
thrive or attain perfection in a soil having one of 
its constituents present in insufficient quantities. All 
the literature available on salt as a manure re- 
fers to it in the cultivation of cereals and roots, and 
for these salt in minute quantities is sufficient. To 
say that because salt does not invariably yield adequate 
results in European agriculture, therefore it cannot 
be of m anurial value in the cultivation of a product whose 
natural home is on the sea-shore, is to assert what 
cannot be assented to by those who have giveu the 
subject of agriculture due consideration, as being op- 
posed to reason. Salt has an indirect value besides. 
It has beenj termed a digester, because it acts in 
the soil as a solvent and liberates ammonia, potash 
and phosphoric acid, tho three principal constituents 
of all plant food. Another property of salt to which 
I draw attention is its ability to draw to it the water 
of the atmosphere. This property of salt renders it 
of very high value in regions where a lack of mois- 
ture reacts very prejudicially on the crop. Happening 
to turn over the leaves of the 2nd volume of the 
Tropical Agriculturist, I accidentally came across 
a contribution on " Manures as absorbents of water " 
by Stephen Wilson, who is I believe Consulting 
Chemist of the Highlaud Agricultural Society. The 
lessons he draws from a series of carefully conducted 
experiments have a special bearing on the subject I 
am now discussing. He says :— "If in a dry season 
a, given manure has the property of absorbing moisture 
trora the atmosphere more copiously tban the soil 
with winch it is mix, : d, the roots of plants growing 
m that sod and manure will be better supplied with 
water tban if that manure were absent." All will 
It to that proposition I am sure. He experi- 
mented with various manures and found that while 
ground coprohte absorbed 3 per cent of water the 
potato manure absorbed <r2 per rent. The hygrosorptive 
properties of other manures were intermediate between 
hose two extremes. To find out the composition of 
Mir pota o manure I consulted Ville and find it 
composed of A.cid Phosphate of lime, Nitrate of Potash 
(salt-petre) and Sulphate of lime (gypsum) : substances 
al more or less having .no affinity for moisture 
It is interesting in this connection to explain bow 
the roots get water. Mr. Wilson says where the roots 
are in direct contact with water, in its liquid form 
the matter is plain, but not so when water is not 
found m a liquid state. For the purpose of deter- 
mining tins he grew certain seeds in glass vessels 
niiett with stones and free open soils, putting th»m 
near the edge of the vessels. Whenever roots made 
their appearance near the sides, he examined the 
root-hairs with a glass and found them covered with 
small particles of moisture. His conclusion on this 
discovery was that in dry soils roots do not go in 
search of moisture, but water seeks them and settles 
on them in a condensed state. " Now a manure that 
has a highly hygrosorptive capacity will keep the 
soil around the roots of plants well oharged with 
moisture; evaporation will fill the interspaces of the 
soil with vapour, and will thus enable the moisture 
withdrawn from the air to be condensed on the roots. 
If any part of plant food — ammonia for example — 
may be vapourised and condensed within the vesicles 
on the roots a different view is opened up." "Two 
main causes combine to render hygrosorptive manures 
rapid in their action, they are soluble and they have 
the capacity of absorbing the moisture which renders 
them fluid." " The more powerfully a manure ab- 
stracts moisture from the air, the more powerfully 
will it resist the giving it up again. During the night 
moisture will be drawn from the air, or during the 
day a part of this moisture vapourised within the 
soil will be condensed upon the root-hairs in the 
form of miuute dew drops to water the plant." Can 
anyone doubt after this testimony borne to the value 
of hygrosorptive manures by a scientist after a course 
of prolonged experiments, that, salt, apart from its 
manurial value, has a value all its own as an appli- 
cative to lands suffering from annual drought ? 
It has just struck me that I have experience of 
the use of salt as a manure for coconuts. On pleading 
for silt as a necessary adjunct of coconut cultivation, 
and for application to a backward field of young co- 
conuts some years ago, a quantity of ham salt was 
placed at my disposal. I applied a coconut shell-full 
of it to each plant after disturbing the soil round 
it slightly. Seeing the plants every day I was not 
able to notice any change in them, but a gentleman 
who saw them after an interval remarked that they 
had grown much since. Mr. Davidson of Jaffna — who 
was perhaps the most able mau engaged in the culti- 
vation of coconuts, judging by his controversial letters 
on the cultivation of coconuts addressed to the Observer 
and embodied in " All about the Coconut Palm," and 
which shew up a high authority on cocouut3 at the 
present day by whom the Observer always swears ; aud 
who was further the Gamaliel at whose feet Mr. 
Jardine, a high authority at the present day, sat — 
uttered no uncertain sound on the value of salt in 
coconut cultivation. He write < :— " Were I to say it 
(salt) acts as a stimulant, I might state what I could 
not explain ; but I could point to its operation in 
the animal economy, as proof of its possessing pro- 
perties, adapting it peculiarly to a tree in which ever 
circulating sap is perpetually varying in constitution 
and density. We can thus understand why the coco- 
nut tree thrives best where it feels the influence of 
spray." He says the quantity of salt a tree requires, 
as determined by analysis, does not exhibit fairly its 
relative value as a manure, because analysis can 
t ike no cognisance of the properties belonging to 
salt. This is instanced as a case where practice triumphs 
over theory. " Salt is the manure he must have." 
Dr. Gardner is quoted as saying that in the Brazils 
a man would walk a great distance, pay high for a 
load of salt and apply it to one single tree ! For 
the sake of its salt, the Jaffna planters used to send 
their cart-i to i he beach to gather aud bring sea weed. 
If as high a value was placed on salt as a manure for 
coconut trees in regions within the influence of the 
sea spray, surely we have displayed lamentible ig- 
norance in ignoring its value in inlaud districts, 
I see the Observer challenges the statements that salt 
is used in paddy cultivation, and that it is destroyed 
by Government at a high co t. You are responsible 
for the former statement. To my knowledge, salt 
is considered inimical to paddy cultivation, but th s 
prejudice is senseless and is based ou paddy being 
killed outright ou laud which during floods is submerged 
by salt-laden tidal waves from the sea. Why, such 
submersion will be enough to kill even a oocouut 
tree. Salt cannot be entirely washed out of such 
