205 
of the balls thus affected, in search of some sort of an antiseptic, 
and am pleased to say that my endeavors have produced satisfactory 
results. At this stage I should acknowledge that my experiments 
have not been exhaustive, since I only applied my testjfc; to small 
quantities. It remains, therefore, to be seen whether or not the 
application of the same antiseptics will be equally efficacious when 
applied to large masses of the affected gum. I am afraid not, and 
in all that concerns the healthful preservation of the gum I incline 
to the maxim that it is better to prevent an evil than to provide a 
cure for it. 
Unfortunately the greatest enemy to our Congo rubber trade 
is the reputation, fostered by others, that there is not a pound of 
absolutely healthy Congo rubber to be found in Antwerp. Equally 
unfortunate is the fact that there is no fixed rule whereby the de- 
generation or depreciation in the value of rubber from oxidation may 
be satisfactorily computed. I will give here an example of the 
difference in price obtained for two lots of the same consignment 
of rubber of which one lot was perfectly healthy and the other in 
poor condition. The lots were of about five tons each. The first, 
which we shall call lot A., was sold for 5.50 francs per kilo. Of the 
second lot, which we shall call lot B., two tons were wholly sound, 
and three tons more or less sticky (about the normal proportion). 
Lot B. sold for only 4.90 francs. Compared then with the price 
obtained for lot A., lot B. suffered a discount of 60 centimes per 
kilo, or about 3,000 francs ($600) for the 5 tons. 
From this case, however, we must not augur that all the lots 
containing portions more or less viscous suffered a depreciation 
of 60 centimes per kilo, upon the prices paid for healthy rubber. 
On the contrary, the discount is sometimes more and sometimes 
even less ; this figure is by no means fixed, and the loss depends upon 
the quantity of the affected gum and the degree of the oxidation. 
However, when we consider that the greater part of the lots 
emanating from the Congo region are more or less tainted, we may 
easily calculate the importance of the loss on the total caoutchouc 
production of the Congo , — The India Rubber World, October 1, 1902. 
GENTSCH’S “ NEW GUTTA-PERCHA.” 
The method of producing the substitute for Gutta-percha referred 
to at length in The India Rubber World of September 1 (page 385) as 
the “ New Gutta-percha” is the invention of Adolf Gentsch, of 
Vienna, and covered by patents, granted first in Austria-Hungary, 
and later in Germany and elsewhere. The German patent is 
No. 116,092 (date of application June 24, 1899), the specification 
for which states that the method consists of the mixing of India- 
rubber with vegetable wax. after which thickened oil may be added. 
The mixture is kneaded in a slowly rising temperature, which may 
be done to advantage in a kneading machine, care being taken not 
to bring the temperature so high as to melt the wax. A fixed 
proportion of ingredients cannot be prescribed. Waxes having a 
high melting point are used alone or mixed with thickened oil, as 
