712 
Supplement to the " Tropical Agricultunat." [April 2, 1894. 
OCCASIONAL NOTES. 
A maund of Jute seed, received from Calcutta, 
has been distributed among the agricultural 
instructors for experimental cultivation in 
their gardens. 
The seeds of Ramie {guizotia oleifera) from the 
crop raised at the School is being kept for a 
second sowing. It is intended at the next seeding 
to supply instructors with small quantities 
for trial. 
Ground-nuts suitable for planting are not 
easy to get in the Colombo markets. Locally 
procured seeds have been lately sown at the 
School, but their germination is unsatisfactory ; 
it has therefore been decided to export fresh 
seed from India. Some years ago Mr. A. W. 
Jayawardene, late headmaster of the School, 
planted out a fairly large piece of land with 
the nut, and with excellent results. Of late 
■we have had enquiries as to where seed nuts 
could be obtained. 
The Government dairy was declared a free area 
(from the infection of cattle disease) on the 
17th March, on which date it recommenced to 
supply milk. 
Mr. W. A. de Silva, who has been studying 
Veterinary Science at the Bombay College, goes 
up for his final examination this montli. Mr. 
de Silva has had a successful career at Bombay, 
and provided lie satisfies his examiners, he will 
be back at the School in May next. 
"We heartily welcome hack to the Island Mr. 
H. W Green, through whose instrumentality the 
School of Agriculture was founded. Mr. Green is 
reported to have greatly benefited by his visit 
to England which his poor state of health 
necessitated, 
ORIGINAL SOURCES OF COMBINED 
NITROGEN. 
It is now generally accepted that plants are 
unable to utilize by means of their leave.s the 
pure nitrogen gas which constitutes about 79 per 
cent of the atmosphere. At one time it was 
thought that plants were able to do so, and 
it was even said that certain Continental experi- 
ments went to prove this to be a fact ; but 
later investigations have shown that plants 
cannot assimilate the free nitrogen of the 
atmosphere. The two main sources of nitrogen 
to the plant are the organic nitrogen in the soil, 
and the nitrogenous compounds that are washed 
into it from the atmosphere by rain (no ac- 
count is hei'e taken of the small quantities 
absorbed directly by plant or soil, chiefly as 
amaonia). The combined nitrogen from the 
two abovementioned sources are taken into 
plants by means of their roots, after having 
iindergone nitrification, — that is, converted into 
nitrates — by the nitrifying germs present in the 
soil. The organic nitrogen in soils is of course 
traceable to the or ganic matter contained in 
them — from whatever source derived. The com- 
bined nitrogen in the atmosphere is on the other 
hand traceable to two sources : — (1) To org&nic 
(vegetable or animal) matter, which liberates um- 
mo:iia during decaj- and combustion (the ammonia 
which is given off being eventually oxidibed in the 
atmosphere, into nitric acid) : (2) to an original 
source of combined nitrogen, whereby the 
combined nitrogen is formed from its elements 
in the atmosphere. Warrington thus refers to 
this latter source: " The nitrogen, and oxygen 
of the atmosphere combine under the intiuenc« 
of electric discharges, nitrous acid being formed ; 
this is converted into nitric acid by the 
oction of ozone or peroxide of hydrogen. 
This formation of nitric acid in the atmo- 
sphere is the only original source of combined 
nitrogen on our globe, the existence of whicli 
has been placed beyond disptite." The extent 
to which combined nitrogen would be formed 
by this means is thus evidently dependent on 
the degree of electric disturbance in the at- 
mosphere ; and the recognition of this fact 
may account f jr the supplies of nitrogen which 
are secured by crops in tropical countries 
where electric disturbance is so common an 
experience. The statement made by Warrington 
that the formation of nitrogen compounds from 
their elements undtr the influence of electric 
discharges is the only original source of combined 
nittogen would now have to be modified : for 
within the last few years, a new original source 
of combined nitrogen has been discovered, viz., 
that resulting from tiie action of the bacteriods 
in the root-tubercles of certain leguminous 
and other plants. There are thus two original 
sources of combined nicrogen. The first-men- 
tioned cepends on natural causes which are 
practically beyond liuman control ; for though 
it may be possible to artificially create electric 
disturbance in the atmosphere, it is hardly 
practicable to adopt this means with a view 
to benefit crops on a prescribed area. But the 
formation of nitrogen compounds in the .soil 
itself, through the agency of certain plants, is 
a possibility which it behoves the cultivator 
to take good note of and to endeavour to 
realize in his agricultural practice. 
NOTES FROM THE NORTH. 
15. The Jaifua cultivators do not believe in 
having all their eggs in one basket. The failure 
of the paddy crops cannot be an uncommon 
occurrence in a place where they have to depend 
for the water solely on pluvial irrigation which 
so often provides oniy a very scanty supply : and 
the people are too well aware of this fact to be 
remiss in growing a good stock of other food 
crops by way of providing against .«uch a con- 
tingency. Tlie fine grains such as " kurakkan" 
(Eleusine corocann\, "Varagu" (Panicvm mi/ui- 
ceum), "Thinai" (Pam'cum ifaltcvm), Shami 
{Paniaim miliare) and various kinds of yams, 
roots, beans and pulses are freely grown ; and 
a valuable addition to the food supply is afforded 
by tlie groves of plantain and bauuiia trees vehich 
are gi'own in separate enclosures with perh.ips 
one or two pumpkin creepers here and there. 
16. The poorer classes ot tlie rustic population 
of the North are a hard-Workitig, healthy, ro- 
< bust and contented set. " Mam wants but 
