6so 
THF TROPICAL AGRICULTURIST. 
[April e, i88i> 
being referred to, quoted Dr. Eatton's valu- 
able Handbook of Salt (a mine of useful 
information on the subject) showing that from 
the chemical constituents of the residual matter 
left after the concretion of salt, such substances 
if applied directly to tea were likely to have 
not beneficial but deadly effects. Various opin- 
ions were elicited, generally to the effect that the 
only really valuable constituent of salt resi- 
duum was potash, the expense of eliminating 
which was prohibitory. Costly refrigerators would be 
necessary. Finally Messrs. Hall, Wilson & Co. of 
Cocanada stated their intention, with the sanction 
of Government, to give a full trial to the pre- 
paration of the by-products of salt, in connec- 
tion with the manufacture of the main product. 
Government are also ready to facilitate experiments 
for obtaining gypsum (of considerable value as 
a manure) and magnesium sulphate from the 
bitterns and the condensers. We may, therefore, 
hear more about the value of salt and its by- 
products as manures.- Meantime we quote the 
main portions of the paper on the subject which 
has reached us from the Government of Madras. 
First comes Mr. Mackenzie's curious letter, in 
which he states : — 
You are doubtless aware that tea planters in India 
are unable to compete with the planters of Oeylon as 
regards the quality and the quantity of tea produced 
as evidenced by the very high prices commanded in 
the market by Ceylon teas. In explanation of this 
generally accepted fact, planting authorities have come 
to the conclusion that the climate of Ceylon must 
be unusually favourable for the cultivation of tea. 
After considerafcioa I venture to say that I believe I 
can account for this advantage enjoyed by Oeylon as 
follows. The sea-breezes from surrounding ocean play 
freely over the whole of the island, so much so indeed 
that many accounted for the late disease of the 
Eucalyptus globulus trees in Ceylon as being produced 
by the excessive saline deposits carried over the island 
by the monsoon winds.* You are well s»ware that 
these saline particles, latent in the ocean breezes, 
consist of ordinary salt, and that salt is chiefly com- 
posed of chloride and various salts of soda. Chloride 
of sodium and salts of soda, you are also aware, are 
next in importance to potash and phosphoric acid in 
the composition of the tea leaf. The superiority then 
of Ceylon teas I attribute to the presence of these 
wind-borne saline deposits, and if planters in India 
could in any way obtain salt as manure, the produc- 
tion of tea in India would be immensely improved 
both as regards quantity and quality. I have the honor 
to ask whether there is any deposit or scum of the 
salt-pans which, useless in a culinary sense, might not 
be utilised as manure. With regard to using the 
ordinary culinary salt as a manure, of course the price 
of that article is utterly prohibitive. I have further 
the honor to request whether you will be pleased to 
give this suggestion consideration and a fair trial. If 
a quantity of useless deposit from the salt-pans was 
supplied to me at a nominal rate, I should be most 
happy to give it a careful trial, and I do not wish 
this suggestion to be made public until a trial has 
been given it. I beg to invite your attention to a 
letter I am addressing to the Madras Mail on "Func- 
tional exhaustion of plant life." 
Mr. Bliss, the Salt Commissioner, on being re- 
ferred to, remarked : — 
The concentrated residual brine (better known as 
"mother liquor" or "bitterns") loft iu the pans after 
the manufacture of salt would not, in .my opinion, 
* That was our theory, and we have no doubt that 
many intelligent observers agreed with us. The 
Planters' Association attempted, through the help of 
.Mr. John Hughes, the eminent chemist, to test the 
amount of salt in the monsoon rainwater. But the 
use of contaminated vessels for transmission rendered 
the experiment nugatory. It might well be repeated. 
—Ed, 
serve as manure and would, I imagine, soon kill any 
vegetation with which it might be brought into con- 
tact. 2. A reference to page 235 of Rattou's hand- 
book of common salt shows that at 30° Beaume, at 
which strength the bitterns should be discharged, 
they contain in 100 parts — 
16'6 parts of Magnesium chloride, 
4*6 „ Sodium do. 
2 - 0 „ Magnesium sulphate, 
a composition which (I speak under correction) is 
not adapted as manure to any form of vegetable life. 
3. I would suggest that Mr. McKenzie should turn 
his attention to the residual brine available in the 
fish- curing yards on the West Coast, which would pro- 
bably form a most excellent manure for tea as well 
as for other plants. 4. This residual brine is com- 
posed not only of a very strong solution of salt, 
but also of fish-blood, entrails, &c, expressed dur- 
ing the process of curing. 5. At present this brine 
is either thrown away or is applied to coconut trees, 
the yield of which, I am told, is enormously increas- 
ed by such application. 6. Under suitable arrange- 
ments large quantities of this brine could be put into 
casks or other receptacles and sealed up in the yards 
tor despatch to the Wynaad or elsewhere, and I have 
no doubt the fish-curers would hail such an arrange- 
ment with satisfaction as they would thereby recover 
a portion of their original outlay on the salt they 
purchase for curing purposes. 7. If Mr. McKenzie, 
or anyone else desires to try the experiment, I shall 
be glad to do all that lies in my power to further 
his views. 8. Another possible source from which 
a supply of salt for manure could be cheaply obtained 
is the saltpetre factories at Coimbatore and elsewhere. 
At Coimbatore alone over 3,000 maunds of impure 
salt is annually educed in the refineries situate at 
that place and at present there is much difficulty in 
gettiDg rid of it. Arrangements could probably be nmle 
by which persons desiring to have this salt for manure 
could obtain it on payment of the cost of denatural- 
isation at the refineries by the admixture of poudrette 
from the municipal latrines, added, perhaps, to a 
nominal sum paid to the refiners, who will be only 
too glad to be spared the expense of destroying the 
salt as they have to do at present. 
Agricultural readers will appreciate the practical 
value of the suggestion to utilize the refuse of 
the fish-curing yards, and coconut planters will 
make a special note of the good effects attributed 
to this material as an application to their staple 
product. When fish-curing yards in Ceylon in- 
crease in number, the practical value of salt and 
fish refuse will doubtless be fully tested.. The 
only objection we can think of, the breeding of 
insect life in the fish refuse, would probably be 
obviated by the proportion of salt present. 
The correspondence we have -quoted took place in 
1885. On 4th May 1888 the Board of Bevenue 
recorded a resolution, portion of which we quote : — 
In the following year considerable further corre- 
spondence followed between this department and Mr. 
McKenzie on the question of the use of " bitterns " 
as manure, in which he urged the value of salt as 
a manure for leaf crops and therefore for tea, and 
the advisability of utilising the "bitterns "to furnish 
it. In the course of this discussion Mr. Benson, the 
Assistant Director of Agriculture, pointed out that 
young leaf crops required potassium and not sodium 
salts, and that the " bitterns " in addition to the 
solids mentioned by Ratton, probably contain a con- 
siderable amount of the former salts ; and that, though 
it was not advisable to use the bitterns as a manure 
direct, they might be utilised for mixing with manure 
heaps, if the. cost of carriage were not prohibitive ; 
and noted that the question whether the separation 
of the different bye-products could be profitably earned 
out in India could not be answered. In subsequent 
letters Mr. McKenzie, though still contending for 
the general use of " bitterns " as a manure, admitted 
that the difficulty in dealing with them was the 
cost of carriage, and agreed with Mr. Benson as 
to the difficulty iu extracting the bye-products. 
