654 
THE TROPICAL AQRlCULTURlST. 
[March 2 , 1891 , 
no silica to get rid of, and its ordinary processes of 
nutrition can progress uninterruptedly. 
The breakiog up of the soluble silicate * could be 
as well accomplished by the perfect aeration of the 
soil so that every particle could be constantly exposed 
to fresh portions of aerial carbonic acid and oxygen : 
and this is one great reason why fine deep tillage, 
where it is possible, so improves clayey soils, but of 
course a tillage that will bring about the perfect 
aeration of heavy clay, is all but impossible ; there- 
fore the advantage of judiciously using lime. 
The soluble alkaline silicate which, when undecom- 
posed, passes into the plant in the water-stream through 
the roots, is evidently very soon split up by the 
vegetable, and the silica combined with some substance, 
such as an aldehyde, and carried on in solution in this 
state to the peripheries of the stem, &c,, where, by 
the process of practically unrestrained evaporation, 
the compound is again split up, the aldehyde going 
off into the air, and the solid silica remaining stranded 
in the cuticle and the other walls, or occasionally 
even in the cavities of the epidermal layer, 
The silicate of lime formed in the above reaction 
itself ultimately undergoes decomposition by natural 
water containing carbonic acid, but the decomposition 
is always complete ; it devolves entirely into carbonate 
ot lime and free insoluble silica. — Alexander 
JOHNSTONEj Edinburgh University. — Nature. 
^ 
COFFEE CULTIVATION IN SOUTH 
AMEEICA : 
A SxNDldATli Organised to Explore the Eastern 
Slopes of the Andes, 
This mail brought us a letter from an ex-Ceylon 
planting friend announcing that there was a project 
on foot in London to send out an exploring or 
pioneering party to Peru with reference to taking 
up land suitable for coffee. The great prospective 
scarcity of this article — prices even now approxi- 
mate to 140s a owt. — forms the speoial inducement 
or this mission. Its inception seems to be due 
to men of high commercial standing in “ the City” 
and among the supporters named to us are .Sir 
Alfred Dent and Sir Hugh Low. So much for the 
mail news contained in our private letter ; but a 
new and more practical interest is given to the 
scheme by the fact that she London Syndicate 
have telegraphed out to Ceylon to get the servioes 
of Mr. P. D. Clarke of Dr. Trimen’s staff, to join 
the exploring party. Mr. Clarke who is a son of 
a well-known Curator of the Glasgow Botanio 
Gardens, has now been 11 years in Ceylon, giving 
faithful though unobtrusive service for all that period 
•without any leave of absence, in our Eoyal Botanic 
Gardens. Under these circumstances, the Govern- 
ment could scarcely do otherwise than grant the 
leave of absence required to enable Mr. Clarke 
to discharge the temporary duty now required of him. 
He gets leave lor nine months and goes to London 
by the Orient steamer ” Cuzco” tonight. The ex- 
pedition so far as Mr. Clarke knows is bound for 
the Eastern elopes of the Andes near, curiously 
enough, to the town of Cuzco and no doubt ad- 
vantage is to be taken of the trans-Andean 
raEway to make the West coast the outlet 
of such plantations as may be established, 
The only .other member of the Expedition so far 
ns Mr. OlarkC knows is Mr. J. L. Sband and 
“ coffee” culture the main, if not the only 
object in view. No uoubt the duly of MpsBrs_ 
fShand, Clarke and their colleagues will be tp 
* Only the alKaii inetals, of which potasaium and 
■odium are the only two that normally occur in soils, 
from Bilicatca soluble iu water. 
report on the fitness of available land for planta- 
tions, on the climate, soil, means of access, 
labour, &c. Possibly, if all go well, nurseries 
may at once be established and clearings be 
commenced. With Sir Alfred Dent on the Syndicate, 
we should suppose there may be an idea of 
importing Chinese as labourers. 
In Ceylon, Mr. Clarke in a quiet way has been 
giving a good deal of attention to coffee. He 
'strongly shares our opinion that planters of Liberian 
ooffee some ten years ago were in far too great 
a hurry to give up the cultivation. His own ex- 
perience last year on half-an-acre planted with 
Liberian coffee at Peradeniya is worth giving : it 
is that he netted E2z2‘62 from the crop off hall 
an acre. Allowing for special attention to the trees, 
there is margin enough here surely to encourage 
any one to go in for Liberian Coffee on suitable 
areas of soil in Ceylon. 
Meantime we' hope to have interesting intelli- 
genoa of the doings of the Trans-Andean Coffee 
Expedition of 1891, and we wish the party all 
success. 
COCONUT CULTIVATION IN THE IN- 
TERIOE OF THE WESTERN PROVINCE 
1890. — The coconut crop of the district has been 
an average, and the price of copra has kept well 
up, so that, on the whole, proprietors with mature 
estates have nothing to complain of ; but the defi- 
cient rainfall from May to October will tell against 
the outturn of 1891. That is the season of the 
heaviest gatherings, and the rainfall at that season 
regulates the crops of the corresponding months 
of the following year to a great extent. 
Towards the end of the year, leaf disease reap- 
peared, but not nearly to the same extent as two 
years ago. In some few cases the same trees are 
affected as suffered then, but not all, and some fresh 
oases, nothing of any consequence, however, 1 believe 
it to be the result of drought on stiff soils that 
too easily yield up their moisture. 
1891 has opened well in the way of rainfall, 
January having given 3T4 inches and it is thunder- 
ing all round while I write. W. B. L. 
^ 
Planting in Guatemala. — We learn that Mr. 
W.J. Forsyth, formerly of Maturata, is getting on 
well as manager of extensive coffee and cinchona 
plantations in Central America. Labour is the 
chief difficulty. We hope to have a letter erelong, 
bringing up Mr. Forsyth’s experience from the date 
of his last communication. 
A Thirty-five Years’ Cycle of wet -and dry 
periods alternately has just been worked out by 
Herr Bruchen, who shows that, — 
In Western Europe and Bastern North America the 
wet period, he shows, gives from a sixth to a fifth 
more rain than the dry period. In Siberia and the 
Far West of North America they give a third to a 
half more rain. Since 1870 the world has, in his opinion, 
been passing through one of the wet periods, which 
has produced bad harvests on tkie seaboards but greater 
fertility in the middle parts of the continents. Dur- 
ing the first 20 years of the next century he expects 
another dry period to come, having an annual humi- 
dity of from 15 to 20 per cent, less than at present. 
Herr BrUchner also endeavors to show that the great 
general migrations of mankind are and have been con- 
nected with these periods. 
But in thp tropics and Ceylon especially, Herr 
Bruohen would find eleven year cycles nearer the 
mark for the altjernations. 
