Nov. 1, 1898.] 
THE TROPICAL 
AGEICULTURIST. 
337 
THE RUBBER SOURCES OF BKAZIL. 
Wa have been asked " How many rubber trees are 
actaiiUy known to exist wilhin any given area ?" The 
number varies very much, as the trees are not planted 
artificially but are on the spot where nature has put 
them. Generally speaking each workman lias about 
100 trees under his control, a greater number not beii;g 
advisable as a s the work would then probably not be 
done with the proper care. A narrow v/ay or path 
leads from one tree to another. Sometimes it takes 
three or five minutes to get from one tree to the next, 
while in other i.istances a lari;e number of trees is 
found within a small space. If the distance between 
the trees is too large, the work of gathering rubber 
cannot be done profitably since the laborer is obliged 
to make each day a certain quantity of rubber in order 
to be able to meet his expenses. Besides the milk 
remains liquid for only a certain space of time, so that 
the workman is bound to limit his work of tapping 
within a certain distance from the hut where the smok- 
ing or curing of the milk is performed On the upper 
rivers the result of a man's work duririg the season — 
from lUarch to October — varies between 400 and SCO 
kilograms of rubber, 600 kilograms being a fair aver- 
age. We think that a certain number of rubber trees 
die annually in the Islands district, but these probably 
are succeeded by new plants as nature continues pro- 
ducing them. The production of Islands rubber has 
been increasing on a moderate scale from the beginning. 
Some rubber estates are exhausted to such an extent 
that people are more or less obliged to abandon the 
work, but other plantations, which wereabandoned some 
years ago and which liave had time to rest, are now 
giving satisfactory results. On the upper rivers, espe- 
cially on the Madeira, the owners of the rubber 
plantations take great care of their property, most of 
them giving the trees a rest of a full year after having 
tapped them during a season. 
There is undoubtedly still a lai'ge number of virgin 
rubber forests, especially in the Amazonas district, even 
in those districts already privately controlled. It 
happens often that on a sudden a large plantation is 
discovered quite close to a place where rubber-gather- 
ers have been living for many years Besides, the 
terms "exploded" or "discovered" refer simply to 
a small belt of land along t he rivers, the interior 
remaining almost unknown. The cost of acquiring 
such land differs very much, due especially to its posi. 
tion. — Iii'lia RuJihc)- irorld, Sept. 1. 
COAGULATION OF RUBBER-MILK. 
The extensive use of India-rubber in the arts and 
manufactures, renders the production of this sub- 
stance a matter of general interest. One of the 
most important problems that awaits solution is a 
simple and effective means for coagulating the rub- 
ber-milk and producing aa article free from im- 
purities and ca])able of beiug worked with as little 
preparation as possible. In the following paper, 
which has recently appeai-ed in the Annals of Bo!ci»>/ 
(Vol. xii.,pp. If..')— 171), Mr. R. H. Biffen, b..a.., De- 
moijitrator in Botany at the University of Cam- 
bridge, has given an admirable summary of what 
is already known on the subject. Mr. Biffen accom- 
pancd Mr. E me Howard last year on a tour tiirough 
tUo rubber-yielding countries of Tropical America. 
They visited Mexico, Central America, Brazil and 
some of the West India Islands. Mr, Biffen has 
therefore had a favourable opportunity lor becoming 
acquainted with the conditions under which rubber 
is at present prepared, and is in a position to suggest 
Bcientific methods for the improvement of the 
industry. * * The summary is very scientific, but 
ends aa follows : — To thoso must be ascribed the 
well-known ' fermentative change ' which causes a 
considerable loss by converting the solid blocks of 
rnbber into a foul-smelling spongy substanie. In 
the Para rubber the creosote absorbed from tho 
smoke of the burning nuts acts as au auti- 
geptiQ and prevents this pr^jteid decompositiou. To 
test for the coagulated proteid is not an easy 
matter; continued boiling with a concentiated solu- 
tion of caustic potash will, however, extract small 
quantities of alkali-albumin. ' Baiata ' gives good 
results mast readily. On extraction with caustic 
potash a flocculent precipitate is obtained, which 
is readily soluble in dilute nitric acid, and is re- 
prccipuated on the addition of alkalies. Boiling 
precinitates it either in acid or alkaline solutio -s, and 
it gives no precipitate with acetic acid and potissium 
ferro-cyanide. The proteid is thus indentical with 
th3 albumose, described by Green, from the latex 
of .Uinui:ops fjlobosa.—li. H. Biifex, Botanical Labo- 
ratory, Cambridge February, 1893, in Kcw BuUctin 
for August. 
PRODUCE AND PLANTING. 
Tea Soup.— Apparently there is still some slight 
misapprehension about the right method of tea inf jsion 
in an answer to a correspondent which appears in the 
columns of an evening paper we note the following : 
btewing tea for sixteen or eighteen minutes is to 
utterly spoil the finest tea, and the surest way to 
cultivate dyspepsia." Tea planters may struggle to 
produce high quality teas, and grocers may advertise 
the '-finest tea the world produces," but if the con- 
sumer indiiferent to the labour wasted on his behalf, 
will continue to make soup from the leaf, and thus 
untimely perish of dyspepsia, what is to be done'' 
Printea instructions are of no use; lectures fail of 
their purpose ; the warning voice of tbe medical journals 
13 in vam. Economy is the great idea, and as long 
as the brew, once made, will bear the addition of hot 
water and keep some sort of colour the popular 
superstition be'ieves that it is both healthful and 
invigorating any time during the day or night, even 
though the leaf ba stewed to something approaching 
a pulp in the process. In this connection it may be 
pointed out that tea drinkers not only have a ditiiculty 
in procuring drinkable tea at railway refreshment 
rooms, tut in some cases they cannot get it at all. 
We notice the complaint of a Colonel who writes to 
the paners from the Army and Navy Club stating 
that although he wired to Basingstoke station that 
tea might be ready on the arrival of his party by a 
certain train, none was forthcoming. The Colonel 
adds pathetically: "A little boy was wandering up 
and down the platform with a pile of trays, each 
containing a diminutive plate of bread and butter, 
a teacup or so, and a teanot ; but the latter on 
inspection, contained only dried leaves, and these 
nuwatered, are hardly calculated to allay a thirst.'" 
it the Colonel had been in need of beer or whisky he 
would certainly have had no difficulty These matters 
may be of small importance in themselves but thev 
ate factors in the problem how to increase the de- 
mand for tea. 
Electricity and the Growth of Plants —One of 
the most attractive papers read on the closing day 
of the British Association related to the effeSta of 
electricuy upon the growth of plants. Some striking 
experiments w_ere tiescribed, showit-.g how electricity 
hastened the development of plants Under electrio 
inrtuence, fot instance, strawberries vielded a cron 75 
Rgr cent better than that grown under normal con- 
ditions ; vxhilst the time necessary for maturing the 
fruit was lessened by one-third. Some of tho facta 
mentioned wore not now, but the novel theory was 
advanced that electricity nelped the growth of plants 
by enabling them to absorb water in "reater nro- 
portions ; and in the water, of course, there contains 
in solntioh, the mineral matter that goes to form 
the structure of the plant. The whSle question 
however, does not seem to have passed beyond the 
experimental stage, and it is noteworthy that Lord 
Kelvin, who took part in the discussion on the sub- 
ject, did not appear convinced of the souudnoss of 
some of tho arguments used to show the favoarabla 
influence of electricity upon plant growth.-//, and 
C. .'/«!(, Sept, lb, ^ 
