137 
nitric acid is used, the object being to form elastic substances similar 
to linoxyn. Stiffeners such as resin, pitch, tar, acacia, tragacanth, 
and albuminoids such as gelatin or casein, may be added, as also 
“filling” materials, including chalk, magnesia, silica, kaolin, zinc 
oxide, cork, sawdust, chopped feathers, and waste leather. The 
product is vulcanised in the usual manner, frequently with the addi- 
tion of waste or regenerated rubber, and is then used for lower-grade 
goods. The elastic product yielded by heating nitrated castor oil to 
I30 C C., for ten hours is the subject of a patent by the Velvril Co. 
Passing ozone through a mixture of castor oil containing colophony 
and sulphur is a variation of the oxidation process patented in 
America, the product being finally heated with sulphur chloride. 
Ditmar {1906), in his specification for a process for the removal of 
unvulcanised oil by means of solvents, states that the defects in 
substitutes are due mainly to its presence. Gelatin or glue, with or 
without admixture of glycerin, rendered insoluble by treatment with 
formaldehyde or chormic acid, gives another form of rubber substitute. 
The viscous masses obtained by heating carbohydrates, such as sugar 
and starch, are the subjects of patents, as also elastic plastic masses 
stated to result from the action of acetylene and oxygen on a mixture 
of copper and nickel, the metals acting as catalyst. Rouxville (1906) 
filed a specification in France for producing caoutchouc, etc., from 
tcrpenes (turpentine), but did not complete the patent in England. 
The conclusion arrived at is that cheaper rubber of improved quality 
is more likely to be derived from increased production by recent 
rubber-plantations than by artificial production . — The Chemist and 
Druggist , January 1, 1910. Page 19). 
On the effect of Arsenical and Sulphur Fumes 
oh Vegetation, with particular reference to 
the Para Rubber Tree ( Hevea Brasiliensis) and 
Rambong ( Ficus Elastica). 
Note: — With reference to the article on this subject appearing 
in the Agricultural Bulletin, February, 1910, Vol. IX., No. 2, page 46 
et seq. it has been pointed out to me that the data showing the total 
period during which roasting was carried on might possibly be under- 
stood to be fifteen days, and that the “Observations on the fifteenth 
day ” might indicate that the plants had by this time become immune 
to the effects of the fumes. 
On page 4;, under the heading “Method of Roasting,” it is 
stated that the roasting was continued for twelve hours. Only one 
batch of ore of 80 lbs. was roasted for a period of twelve hours and 
the effects produced on the plants were caused entirely by this single 
roasting, the first effects being observed on the second day after the 
roasting had cleased and continuing till over the 7th day, after which 
no further effects were observed, and the plants gradually recovered ; 
the recovery being well advanced and the plants forming a number 
of new leaves by the fifteenth day. 
yy> 
^ idv 
B.J. EATON, 
Government Chemist, F. M. S. 
