88 
Indian Forest Records. 
[Vol. IV. 
CONCLUSION. 
In conclusion the following recommendations for the clarifica¬ 
tion of Indian rosin prepared by whatsoever process may advanta¬ 
geously be summed up : — 
(1) As is done in France and America, great care should be 
taken to avoid the admixture of accidental impurities in the pre¬ 
liminary stages of collection of the crude resin. This can be done 
by keeping the area round the tree under tapping free of pine 
needles, leaves, etc., and by collecting the resin as it exudes from 
the tree in covered receptacles. The crude resin should be trans¬ 
ported to the factory in covered vessels made of corrugated iron 
sheets in sizes convenient for transport. 
(2) The crude resin should be classified in different grades ac¬ 
cording to its colour and quality, which will depend, as said else¬ 
where, on the season and the number of years over which tapping 
has been continuously carried out. The colophony resulting from 
the various grades of resin should be properly graded before send¬ 
ing to the market. 
(3) Melted rosin as it issues from the still must always be heated 
over an open fire to drive off the last traces of the oil. Colophony, 
as produced in the Government Factory at Bhowali, is sticky and 
is coloured greenish by copper salts from the still. The open fire 
heating will free it from the last traces of oil and make it harder. 
It will be less liable to melt in transit. It will have a brighter 
appearance. While heating it over an open fire, it is preferable 
to gradually add about 5 lbs. of water to a charge of about 2 mds. 
of colophony. Even if light coloured colophony is not required, 
it must undergo this treatment. 
(4) Bosin of darker qualities while being heated over an open 
fire should always be treated with crystalline alum as described 
above and if necessary after clarification exposed to sunlight for 
further bleaching. 
(5) It will be seen that any desired shade of colour can be given 
to colophony by clarifying it with a mixture of alum or nitre or 
both, and the shade in demand can be obtained by varying the pro¬ 
portion of the clarifying mixture. 
C 88 ] 
