m 
THE TROPICAL 
AGMCULTURIST. [Nov. 1, 190§. 
Jills, all the old stocks held were most diffionlt of sale, 
and what Wi.^ disposed of showed an enormous decline 
and thus Eubber thit WIS quofcsd at 3 s 2d, a little 
more than a year ago sold at about 2g. 2d, to 23. 5i. 
per lb. accor iing to quality. If good quality of these 
descriptions could be imported to sell at present rates, 
it is certainly -worth encour.aging as with scarceness of 
Good reil, ^lozanb que Ball, the demand for these Red 
Penaug kitdi would again gfow gradually. 
SmiU quantities of Assam were shipped, but the 
quality was very poor and sandy, and consequently did 
not meet with any requirement oc interest. 
Borneo. — Of this Rubber the supplies have not been 
excessive, but in sympathy with the general tendency 
of the market prices declined. The?e grades are still 
held for higher prices, and with a continuano.=) of the 
lower quotations all round we must also look for much 
reduced values in these grades before one will be able 
to effect Urger sales. Pontianak : Supplies were 
^Jjout the same as those of last year and sold readily 
prices showing very little change at the close of the 
year. 
Rubber from Pesnch CocniN-CHiN-A and from Lower 
Qhina have continued to sell well, the quality and con- 
dition of nearly all arrivals were satisfactory and the 
small trade done must have been pcofit»ble to the im- 
porters. 
Java Ribber and New Guinea hive been very 
very scarce, but generally speaking these qualities were 
not in great demand, and quotations were only 
nominal, 
Balata. — We had reduced arrivals of these descrip- 
tions, and all the imports nf the^e grades have met 
with a good dem md, although a,t one time Block 
Balata wa? as low Is. Td. The year closes with 
buyers at 2s and sellers at 2s. Id. Nearly the whole of 
the stock in fiist and second hand has been cleared 
off and gone into consumptioii, and all new arrivals 
are selling very readily at full piices. Sheet Balata. 
— Owing to the increased coas'imption the prices have 
also gradually goner up, and the market closes with 
buyers at 23. 7d., showing 4,1. perlb. advance for the 
year. 
Gutta percha. — The year opened with a very poor 
demand, and the m irket continued weak throughout 
almost the whole of the year. It was only during 
November that, owing to larger contracts for cables 
being pla-ed, extensive buying orders appeared on the 
market, thus inci easing values of Gutta-Percha. and 
since then a fairly large husiness has been done. There 
seems to be every prospect of a continued good market, 
with fair prices being paid for good and desirable 
qualities of Gutta-Percha. 
AGRICULTURAL CHEiSSISTRY. 
The eecond edition of the comprehensive work of 
Professor Deherain on the subject of agricultural 
chemistry* has lately been published, and brings up-to 
date most of the more important investigations con- 
nected with the study of plants, and the cultivation of 
the soil. In his introduction, the author states that 
the plant is an " instrument of reduction," because 
within its cells are separated the element oxygen 
from carbonio acid (dioxide), which is a compound of 
carbon and the element oxygen ; and from nitric acid, 
■which is a chemical compound ot nitrogen and oxygen 
The plant further takes these separated gases and 
unites them with the elements of water, whereby in a 
series of rapid stages they become converted into such 
Bubstancea as sugar, starch, cellulose, oil, and albumin- 
oids. P:'ants are the only organic things that make 
use of the forces of the sun to build up from these ele- 
mentary substances products alike suitable for human 
and animal food. The chief object of the author in his 
voluminous work is to show how the double work of 
reduction and of reconstruction, or building up, is 
* Traitede Qhiinie AyncoU, 2ad edition, 1902, P. P. 
Peberiau. 
carried on ; also how we may obtain by the help of 
plants, a suitable climate, and a properly cultivated 
soil, such a quantity of vegetable products that its 
sale shall be rdmunevative. 
One of the greatest of the practical problems pre- 
sented for solution by agricultural chemistry is the 
conservation ot plant food. With an abundance ot 
plant food, and a favouring climate, it is difficult lo 
place a limit to the power of the eatth for supporting 
lite. Should the cultivator succeed in raising the 
amount of f 'od supply beyond that which his land 
would naturally yield, he is serving at once his own 
interests and those of the public generally, because 
both agricultural and horticultu-al prosperity are 
better secured by the increase of produce than by rise 
of prices. 
The author commences his work with a description 
of the development of plants, including the germina- 
tion ot seeds, and the production and assimilation ot 
plant food. The portion on growth and maturation 
has been considerably enlirged in the present volume. 
Next follows a full dsscription of the importance of 
water; its circulation in 'he plant: the enormous 
evaporation excited by the sun's rays, which the plant 
can only maintain by constantly drawing upon the 
resources of the soil; should these fall, the plant 
languishes and dies. 
The second part of the treatise treats of the study of 
arable land, which is described as a reservoir from 
which the roots of plants havetoobtiin their supply 
of water. It is only a properly cultivated scil that can 
fulfil its chief function of being a store-house ef 
moisture. Water flows away over soil hardened by 
drought; it ''oes not easily penetrate into a sun-baked 
surface ; and bcc iu=e, under such conditions, it remains 
in the top layers of soil, it soon evaporates and is lost. 
On the other hand, water penetrates into a well-worked 
soil, is held in suspension, and remains there until 
wanted. It descends into the lower layers where the 
more deeply penetrating plant-roots feed. The plant- 
food of the soil only has access to the absorbent organs 
of the plant when presented in a p'oper soluble or 
semi-soluble form in connection with water. 
The study of soil ferments has been largely extended 
in this edition ; the author thows how the organic 
matter of soils becomes oxidised, how ammonia is 
formed, and how nitrates are reduced. 
The third and fourth portions of the work deal with 
the subject of m inuring. Considerable stress is laid 
upon the importance of a suitable supply v^ithin the 
soil of soluble available mineral plant-food, 
such as potash, lime, and phosphoric acid. The 
question of green manuring, that is ploughing-in 
growing plants, and the cultivation of autumn catch- 
crops, is recommended, because they retain the 
nitrates formed in the soil during the s.immer months. 
Green manuring further promotes the production of 
vegetable organic matter fhumus) within the soil, and 
prevents the nitrates from being washed away by 
winter rains. Nitrogen in the form of nitrates is 
generally regarded as the best kind of nitrogenous 
food for plants. Plants obtain their nitric acid by 
absorbing the nitrates that are already present in the 
soil, those that are carried down to the soil from the 
air in rain and snow, those that are applied arti- 
ficially in fertilisers, and those that are formed in the 
soil from the nitrogen of other substances. As is ex- 
plained, all the nitrogen that is applied to the soil for 
fertilising purposes, especially in farmyard manure 
and in green-manuring, is not in the form of nitrates. 
It must first undergo certain chemical changes before 
it becomes available to plants. These changes take 
place through the agency of micro-organisms or fer- 
ments ; and that particular process in which the 
nitr. gen of the ammonia-gas is changed into nitric 
acid, which ia called nitrification. Ons of the most 
active periods of the production of nitrates in the soil 
is during the early spring months, when the rootlets of 
growing plants greedily lay hold of it as it is formed. 
It is not only by hindering the loss of nitrogen that 
catoh crops are usefal, bat they alao increase the 
