4 bg 
tion. Nothing prejudices a rubber brand so much as continued 
depreciation of quality. At first, price is considerably reduced, 
and if continued the material is discarded by all good buyers, and 
become relegated to the rubbish heap or unreliable products. 
All this has reference to what one may regard as accidental 
adulteration arising from carelessness. Many rubbers are design- 
edly loaded to gain weight. The readers will note how absurd 
such a policy is, and how ultimately it must result in loss and dis- 
credit. There is, however, another form of adulteration which will 
in time destroy the reputation of any brand and effectively exclude 
it from the markets of the world. 1 his is the designed admixture 
of inferior gums, such as Euphorbia and many others of the resin- 
ous class, with the intention of illegitimately increasing the imme- 
diate profit. But the brand once detected in this condition will 
be for ever disregarded. After due care has been observed in 
collecting the milk, there come the process of curing. This also 
requires the greatest care in order to yield the desired results. 
The method employed by the Amazon workers is to dip a wooden 
paddle (perfectly clean) into the milk can. A layer of sap then 
adheres, and this is coagulated by the smoke from a vegetable 
fibre. The paddle is repeatedly dipped, the object being to have 
each layer as thin as possible so that the whole mass may be quickly 
cured, thoroughly yet not excessively. This is necessitated by two 
considerations : in the first place to ensure that all the sap is tho- 
roughly coagulated, failing which the immature piece will Jose in 
washing from 5 to 20 per cent, and in the second and most vital 
and important place, to secure the freedom of the gum from the 
presence of rubber resins. 
Some eight years ago Professor Henrique, of Germany, made 
some investigations into the causes of the depreciation of the quality 
of vulcanised India rubber under the influences of heat, time and 
sunlight. The effects noted were — that some rubbers become hard, 
brittle and rotten, whereas other rubbers under the same conditions 
retain their old strength and vitality. The Professor traced the 
cause of this to the presence of quantities of rubber resins in the 
defective samples, and explained that the 5 per cent, of sulphur 
originally introduced for the purpose of vulcanisation had formed 
considerably traces of sulphuric acid in combination with the resins, 
which in course of time bad destroyed and rotted the rubber. This 
fact, having been experimentally verified, led to the issue of an 
order by Sir A. M. Rendel, on behalf of the Indian State Railways 
and of the Indian Government, limiting the percentage of rubber 
resins in any manufactured articles to 5 per cent. This test has 
been rapidly adopted by all Government Departments and has now 
become the standard for all high class goods. Hence the manufac- 
turer cannot afford to use any gum which does not meet this re- 
quirement, for he cannot afford to run the risk of rejections. Thus 
it becomes of the first importance to the rubber grower to see that 
hvs product meet this requirement, or he will quickly find his article 
relegated to the position of a third rate brand. Some experiments 
have recently been made with a chemical treatment by alcoholic 
