Tune i, 1882.] THE TROPICAL AGRICULTURIST. 
J °57 
COMPARATIVE TRIALS OF MANURES. 
A correspondent suggests, with respect to Mr. W. 
D. Bosanquet's valuable experiments, that they would 
have been more conclusive if they had been in du- 
plicate. The fact that they were made on squares 
also militates against their value, as each was thereby 
conlined to a particular spot and not applied over 
an average of the sod of the field. It is import- 
ant that in all comparative experiments the con- 
ditions should be such as to make the results reliable 
and conclusive. I would suggest that such experi- 
ments should be made in lines, rather than in squares. 
When different manures or treatments are tried on 
strips, adjacent to each other, from the bottom to top 
of the field, each strip being of about 10 lines in 
width, the results may be compared most readily, 
especially if the field be commanded from some point 
whence the whole experimental area may be viewed 
at a little distance. Moreover, each strip will traverse 
a greater variety of soil, and give more reliable evid- 
ence than any mere patch or square. In an extens- 
ive trial of manures, which I made some years ago, 
10 lines of coffee from the bottom to the top of the 
field were manured or treated in adjacent strips, 
with intervening etrips, here and there, of like width 
without manure, or treatment, to facilitate comparison. 
The results in this case were most conspicuously 
seen, so far as regards the appearance of the trees, 
from a Held opposite. I have not now the record 
of the results of this experiment, nor would these 
esults bo of any general value, though they served 
an important purpose on the particular estate for 
guidance in subsequent more extended operations. 
1 may mention, however, that the manures tried 
were Peruvian guano, Bolivian guano, poudrette, coco- 
nut poouac, bonedust, wooda9hes, lime, &c., and 
some rnixlures of poonac with bonedust, or wood- 
ashes. The main general results were as follows : — 
1st as regards appearance. The strip manured witli 
Peruvian guano was the lirst to show up with a fine 
dark glossy foliage, and was quickly followed by the 
poudrette, poonac, and Bolivian guano, in order, with 
the same characteristics, but in lesser degrees. The 
others showed more or less improvement, but not 
of the same marked character. 2nd, as regards crop : 
unfortunately, a rush of crop over the whole estate 
prevented the possibility of keeping the crop of each 
strip separate. Tho record, therefore, was based 
on observation of the progress made in each strip by 
the pickers, aided by observations in tho field itself, 
and is not so exact as it might have been. The 
palm was undoubtedly carried by the mixtures of 
bones aud poonac, and bones and woodashes. Next 
followed tho bones alone and poonac alone in order. 
3rd, as regards appearance after crop. The strips 
manured with the mixtures looked fit, none the 
worse for their crop, and ready for further service. 
Those with bones alone, aud poonno alone, looked 
rather hss vigorous than those with mixtures. But 
the highly iiinmnniacal manures, tho Peruvian guano 
and the poudrette showed sfvrrt rs iu-tioii. Tho trees 
looked sickly and yellow, with many dead points. 
I refer to thi» experiment, however, less for its results 
'.'15 
than as illustrating the great advantage of the linear 
system for experiments on comparative treatments 
of coffee. 
The importance of preliminary trials of manure on 
a small scale, in anticipation of more extended oper- 
ations, cannot be overrated : and when it is con- 
sidered that, on an area of 25 acres, no fewer than 
10 different treatments may be compared each with 
a strip of 10 lines of 300 trees, or say 3,000 trees 
for each treatment, there is no excuse for blundering 
on a largo scale. One needs not to grope in the dark, 
but may be guided by the liyht, following Mr. W, 
D. Bosanquet's good example. G. \V. 
HYBRIDITY OP CINCHONAS AND CRAFTING 
LKDGERIANA CUTTING ON TO SUCCI- 
RUBRA STOCKS IN THE OPEN AIR. 
Mr. Wm. Smith, who has been so much grieved 
by our defection to a belief in the " hybridity-of- 
cinchonas " theory, and who, when he wrote the 
very interesting and valuable letter which appears 
below, imagined that he was merely a solitary voice 
crying in the wilderness, ought to be greatly com- 
forted by the alliance aud support of so eminent an 
authority, scientifically and practically, as Mr. James 
Gammie, who has so long been in charge of the 
Cinchona Gardens in British Sikkim (Darjeeling). 
To the dictum of Hooker and Thomson, that hy- 
briuity is a process very rare in nature, on which 
we so long founded our objections to the statements 
that hybrids had appeared amongst the cinchonas 
introduced into Java, Ceylon and Iudia, Mr. Gammie 
pins his faith still ; and as for Mr. Wm. Smith, he 
considers the idea of spontaneous crossing as an im- 
peachment of the Being who created all plants and 
gave them their laws of existence and reproduction. 
Messrs. Cammie and Smith can point, as we so long 
did, to the wonderful differences between young aud 
mature foliage and the inveterate habit of sporting 
characteristic especially of the more valuable aperies 
of cinchonas, the crown and yellow barks — ft 
officinalis and C. calisai/a. It is not likely that we 
who on this subject, had the temerity to break a 
lance with John Eliot Howard, the very prince of 
quinologists, should lightly adopt a belief in tl.e 
hybridity of cinchonas. We did so, simply when we 
found all the leading authorities, including Hooktr 
himself, with Crimen aud Moens, — aud, amongst 
practical as well as scientific plauters, Forbes Laurie, 
arrayed on the side of not only possible hybridity, 
but, from what was stated to bo the peculiarity of 
the blossoms, a stroug teudency in that direction. 
In going over tho Java plantations with Mr. Moons, 
we were shewn the bee and tie butterfly which were 
the active agents of the process of adulteratiug tho 
pure Ledgerianas with the pollen from Pahudianas, 
Joscphianas. Hasskarlianas, Javauieas, aud other in- 
ferior sorts, all of which were to bo practically ex- 
tirpated, mo that Bcod whieh could bo depended on 
(a large crop anticipated this scasou, by the way) 
could ho gathered intin the Ledgerianas. Meantime, 
Mr. M"oh.m *<»*, •■>■> rapidly a» po-.ihlo. pushing for- 
ward the gritting process, so as to get a goo«| supply 
