Nov. 1, 1899.] THE TROPICAL AGRICULTUEIST. 
335 
CACAO SOILS IN THE WEST INDIES. 
GoTernment Laboratory, Georgetown, Demerara, 
British Guiana, Aug, 31. 
Dear Sir,— My attention has been directed to 
an article in your issue of July 18th, 1899, in which 
Mr. Cochran has ascribed work done in this 
laboratory by myself and staff to Professor 
Carniocly, of Trinidad. I shall be obliged to you 
if you will give to Mr. Cochran the two pamph- 
lets I have sent under cover to you, the first entit- 
led "The rocksand soils of Grenada" and "The 
agricultural chemistry of cacao" and the second an 
extract from a report on the agricultural work in 
the Botanic Gardens of this colony relating to 
cacao. 1 may remark that the Grenada soils 
were personally selected by myself from the plant- 
ations. 
I have also a series of analyses of the very fer- 
tile cacao and coffee soils of Surinam, which I made 
lor the purposes of comparison wiih the soils of 
the interior of the Colony, which, if they are of 
any interest to you or to Mr, Cochran, I shall 
be' happy to place at your disposal. 
Professor Carniody's analysis are not compar- 
able with oars, as he uses a different method of 
attacking the soil with acid solvents. We have 
for the last 15 years nsed invariably the process 
described in one of the pamphlets. 
I may say that ray experience in the West In- 
dies points to the great importance of the amount 
of potash in an available state present in the 
soil and to the lesser importance of phosphoric 
and nitrogen and this consideration is based 
on the analyses of sixty or seventy different 
soils. 
Thanking you in anticipation for giving the 
pamphlets to Mr. Cochran.— I remain yours 
faithfully, J. B. HARRISON. 
Governraeot Analyst, British Guiana. 
: Having handed on the pamphlets, men- 
tioned by Mr, J. B. Harrison, Government 
Analyst, British Guiana, in his interesting 
letter which appears above to Mr. Cochran, 
as requested, the latter has kindly favoured 
us with the following remarks : — 
City Analyst's Office, Colombo, Oct. 21. 
.'^ I have to thank you for a reading of the 
letter of Mr. J. B. Harrison, Govei'nment 
Analyst of British Guiana, on the subject 
of the cacao-soil analyses, with which I 
dealt in the article you published on 20th 
July of the present year. I am also much 
obliged for the two pamphlets he has sent to 
me, embodying the results of his analytical 
work of many years. 
They represent an amount of original and 
careful analytical work, which only an ana- 
lyst can fully appreciate. I should also very 
much wish to see his analyses of the very 
fertile cacao and coffee soils of Surinam, 
which Mr, Harrison offers to place at your 
disposal. 
(!., Of the two sets of cacao-soil-analyses which 
=1 compared last July, only the second set, 
viz., the analyses of soils, of average fertility, 
was conducted under the supervision of 
Professor Carmody, Government Analyst of 
Trinidad ; while the first set, the analyses of 
fertile cacao soils, was the work of Mr. J. B. 
Harrison, and his staff at British Guiana. I 
am sorry I did not know that Mr. Harrison 
was the analyst till I received his letter 
which you have forwarded. The copy of the 
proceedings of the Agricultural Society, in 
wMch I first saw the analyses (published in 
1897) was incomplete, some pages being 
a- wanting, and amongst them the first page 
of Mr. Harrison's report; but, even in the 
complete form which he now sends me, en- 
titled " Extract from the Report on agrical- 
tural work in the Botanic Gardens relating 
to cacao" and printed by authority of the 
Government, neither Mr. Harrison's name nor 
that that of any other member of the staff 
of the Botanical Gardens occurs ! 
As the two sets of analyses were by differ- 
ent chemists, using different analytical 
methods, they are of course not so strictly 
comparable, as if the same analytical me- 
thods had been followed, but a comparison 
is still instructive. 
As Mr. Harrison has had great experience 
in the Analyses of cacao soils, planters will 
be glad to have the latest word he has to 
say on the subject which is as follows : — " I 
may say that my experience in the West 
Indies points to the great importance of the 
amount of potash in an available state present 
in the soil, and to the lesser importance of phos- 
phoric acid and nitrogen, and this consider- 
ation is based on the analyses of sixty or 
seventy different soils."' 
I find the same view as regards nitrogen 
more fully expressed in Mr. Harrison's work 
entitled : " The rocks and soils of Grenada 
and Carriacow and the agricultural chemistry 
of cacao where he remarks :— " Upon all 
the soils of Granada, light dressings of nitrate 
of soda or sulphate of ammonia will 
prove beneficial to plants and upon the soils 
which appear in the list marked ' nitrogen ' 
such dressings are in my opinion essential 
to successful cultivation." (These last are 
soils in which the amount of nitrogen ranges 
from '032 to "IS? per cent.) " Where such 
crops as cacao, coffee, and nutmegs are the 
staples, it is necessary to use great care 
with regard to nitrogenous manures. Heavy 
dressings of active nitrogenous meanures 
may easily cause excessive leaf formation, 
and result in the fiowers produced dropping 
without the fruit setting, and the antici- 
pations of full crops raised by the brilliancy 
of the heavy foliage, will not to fulfilled. 
In view of this, 1 recommend that nitro- 
genous manures should be supplied to these 
" crops as a rule in light dressings of not 
more than one cwt. of Nitrate of soda per 
acre at the outside, and applied only at the 
time when the main crops of fruits have 
just been picked. If the trees show a full 
leaf development with no signs of flagging, 
nitrogenous manures should not be applied 
as their use may result in more harm than 
good. For cacao, nutmegs and similar crops, 
I consider that nitrate of soda will probably 
be found a preferable source of nitrogen to 
sulphate of ammonia, whilst the latter will 
be found better for sugarcane." 
There are several other very interesting 
points on Mr. Harrison's able reports, to 
which I should like to draw attention, if I 
had the time at present to go into the 
different subjects discussed; but the obj-^ct 
of my present letter is simply to give Mr. 
Harrison credit for the analysis of the set 
of fertile cacao soils referred to in my com- 
munication published by you in July of the 
present year. 
