tm TROPICAL 
AGRICULTURIST. [Jan. 1, 1904. 
THE liATEX GLOBULES ARE NOT KTJBBER. 
A careful examination of rubber lafcex under the 
microscops soon reveals the very interesting fact that 
the minute globules suspended in it are covered with 
an extremely thin film of albuminous matter; but 
v?e further find that the contents of these globules 
do not consist of india-rubber as we Isnow it, but 
of a substance possessing about the fluidity of an oil. 
In other words, these supposed rubber globules are 
not rubber. Of course, it might be euggeated that 
these globules consisted of india-rubber rendered 
liquid by the presence of some substance acting upon 
it in the manner of a solvent, and it seemed to me 
important to settle this question. This seemed to ba 
possible with the following considerations as the 
starting point. 
India-rubber is absolutely insoluble in ether.* If. 
therefore, india-rubber is present in the globules of 
the rubber-milk, it should be impossible to remove 
these globules from the milk by shaking it with ether. 
If on the other hand, these globules do not contain 
preformed india-rubber, but merely a substance 
which by some simple molecular change, say polymeri- 
sation, is transformed into india-rubber, we might 
then expect this substance to be readily soluble in 
ether.t, and therefore, on shaking the rubber-milk 
with ether, the whole of the contents of the globules 
should dissolve in the latter. Under these circum- 
stances, the milky appearance of the latex would 
disappear, and we would obtain a watery, clear liquid, 
with a supernfltant layer consisting of an ethereal 
solution of the mother substance of india-rubber. And 
this is exactly what we do obtain. Working in this 
manner, I obtained with the greatest ease ethereal 
solutions containing up to 43 per cent, of this rubber 
substance. This fact alone is sufficient to demonstrate 
that the contents of the so-called rubber globules 
are not india-rubber, for, even if india-rubber were 
soluble in ether, a 43 per cent, solution of this kind 
would be almost semi-solid ; whereas the ethereal 
solutions I obtained were perfectly limpid, and could 
be filtered with the greatest ease. 
These solutions may be kept in the dark in a cool 
place for several weeks without any apparent change. 
Sooner or later, however, they become distinctly 
viscous, and once this change has become noticeable, a 
few days suffice to convert them into almost water- 
white jellies of surprising toughness. If the ether is 
allowed to evaporate from these jellies by exposing 
them to the air in a cool place, we obtain ultimately 
an almost coIoQrlesa, glassy, and fairly transparent 
substance possessing in a high degree all the properties 
of a very high-class rubber. 
I did not succeed in producing this polymerisation 
by boiling such a freshly made ethereal solution for 
several hours, but on adding to such solutions ether 
containing hydrochloric acid, or a trace of formic 
acid, a very rapid rise of temperature takes place, 
the ether within a very few seconds begins to boil, and 
this boiling proceeds with explosive violence under 
formation of an enormously inflated spongy mass. 
The thermometer at that point recorded 61 deg. C. 
The cavities of this spongy mass are, of course, tilled 
with ether vapour, and on cooling, the whole structure 
collapses, the ether gradually evaporates, and we obtain 
thus eventnally a solid mass in all essentials 
resembling the prodact obtained from the above 
described jellies. 
* Of course, this applies to resin-free rubber. From 
crude rubber ether dissolves the resins contained in it. 
The rubber substance itself ia quite insoluble in 
that solvent. 
t I omit the chemical reasoning justifying this; 
eiBsamptiou, 
ANALYSIS OP RUBBER FBOM ETHEREAL SOLUTION. 
The rubber thus obtained on extraction with ace- 
tone yields about 3 per cent, of a resinous substance 
ideutioal with that obtainable by the same treatment 
from the commercial brands of Castilioa rubber, but 
much lighter in colour. The rubber obtained from 
these ethereal solutions on analysis was found to 
contain 87 89 per cent, of carbon and ll'SO per cent, 
of hydrogen. No doubt, therefore, remains that 
india-rubber, as such is not pre-existent in the india- 
rubber latex, but ia the product formed by a process 
of polymerisation from the thin, oily liquid emulsified 
in the latex. : 
This is not the place to enter upon a full discussion 
of this interesting and vastly important result, but 
I may point out that the above already amounts to an 
almost complete proof that one of the possible terpenes 
of the class known as olefinic terpenes must be the 
mother substance of india-rubber, and that it only 
remains to discover this particular terpene, and the 
means and ways of its produotioc, in order to realise 
the synthesis of india-rubber. These remaining 
problems do not appear to offer any insuperable 
difficulties, though the task cannot be considered an 
easy one, — India-Uubber Journal. 
lERIGATION IN EGYPT. 
THE ■5JILE DAMS. 
Sir Benjamin Baker recently gave some very satis- 
factory information which had not yet been pub- 
lished regarding the beneficial results of the expen- 
diture on the Nile dams. After remarking that 
about £2,300,000 was expended at Assouan, and 
£1,000,000 at Assiout, he went on to say that the 
following conclusions had been drawn by the Egyptian 
Government officials : — The Assiout barrage was in 
operation during the summer of 1902 before there was 
any water in. the reservoir, and when it acted merely 
as a regulating dam to raise the level of the water 
in the river without increasing its quantity. It 
was estimated that the direct and indirect gain was 
not less than £600,000 in one year on an expenditure 
of a million. 
The Assouan dam sluices began to be closed in 
October, 1902, and during March and April and part 
of May the flow down the river was supplemented 
to the extent of one million tons of water daily, 
and this was gradually increased until in Jane the 
quantity was 20 million tons per day, and practi- 
cally doubled the available supply at the most 
critical time for the irrigation of the summer crops 
RESERVOIRS SATE THE COTTON CROP. 
The levels in the river south of Haifa were very 
low in March, April, and the first half of May, 
SO that without the assistance from the reservoirs 
great difficulty in saving the cotton crops would 
have been experienced. The result of the discharge 
was to give an ample supply, with Middle and Lower 
Egypt, at least one month earlier than would have 
been the case without the reservoir, and a cotton 
crop probably amounting to nearly seven miilioa 
cantars, of a value at present market rates of over 
22 millions sterling, was plentifully irrigated. 
RECENT PROGRESS IN MIDDLE EGYPT. 
In Middle Egypt, 170,000 acres of basin land had 
been converted to perennial irrigation, and each year 
more would be taken in hand, np to a final total of 
about 350,000 acres. In two years the rent of the con- 
verted basin land increased £3 per acre, and the 
value of the land £30 per acre, while the cost of 
the conversion, including all drains and irrigation 
works, was £4 per acre. Up to the present, therefore, 
the annual increased rental was £510,000, and the 
increased value £5,100,000 in converted laada only. 
