'Part VI.] Preparation of Turpentine , Rosin and Gum. 
27 
Petroleum benzine is an excellent solvent, and is generally used on a 
commercial scale in the extraction of oils and fats. It gives excellent 
resin of good colour and texture. Its cost is about annas 14 a gallon 
when purchased wholesale. 
Mr. W. E. Fischer, a Chemical Engineer of London, was referred to 
as to the advisibility of using petroleum ether (boiling below 40°-70°C.) 
or petroleum benzine (boiling point up to 110°C.), and he recommends 
the use of the latter, with a good supply of cold water for the con¬ 
densers, whose temperature he says should be below 75°-80°Fah. He 
further pointed out that even at this temperature of 80°F., a solvent 
like trichloroethylene (boiling point 88°C.) is difficult to condense, though 
the size of the condenser especially for work in tropical countries, is an 
important factor governing recovery. 
Turpentine is the best solvent for the resin, and its recovery is assured, 
though it can only be used for extraction by maceration and as such 
large quantities are required, it has not been thought advisable to advo¬ 
cate its use here though, in a running concern, it might be employed 
for maceration with advantage. 
Experiments have shown that the amount of solvent required when 
working by the Soxhlet process, is about three times the weight of the 
oleo-resin to be treated ; whereas when working according to the Macera¬ 
tion process by which the material has to be twice treated, as much as 
ten times the weight of the crude material is necessary. 
Taking into consideration the advantages and disadvantages of the 
various solvents available, Petroleum Benzine is advocated, but as for 
the process to be employed with this solvent see below. 
Trichlorethylene is the solvent also recommended. 
Part V.—Proposed plant, method of extraction and preparation 
of the products for the market. 
1. Plant. 
It must be clearly understood that the proposed plant, of which a 
rough design is given (Plate IV) is purely of an experimental nature, 
as owing to the tests carried out in the Forest Research Institute 
distillery having been made in an adapted still, certain factors remain 
undetermined. 
The plant proposed for further experiments, which interested parties 
may care to carry out, is designed with a view to adopting it as a unit 
of a large-scale factory. Moreover, the design is far from being a complete 
working drawing, and is only intended as a guide to Engineering firms 
as to actual requirements. 
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