32 
Indian Forest Records. 
[Vol. 17. 
Officer, Naini Tal, to the Imperial Institute, London, for examina¬ 
tion, and the second report given in Appendix D embodies the results 
obtained. As pointed out in Chapters II and Y, the Forest Chemist 
has noticed a distinct improvement in the quality of the oil by dis¬ 
tilling it with methylated spirit, and accordingly he sent two more 
samples of both the crude and the rectified oil obtained by distillation 
with acetic acid in the Laboratory to make sure that the samples A 
and B sent from the factory were not mixed up with inferior oils 
produced with dilute spirit as mentioned above. The third report 
in Appendix D gives the results of the examination of these two 
samples as compared with those of A and B. Excepting slight 
differences that are natural in oils derived from different lots of crude 
resin, the report shows the general composition of the Laboratory 
samples to be similar to those made at the distillery. The spirit 
distilled oil rectified by redistillation and by the elimination of 5 
per cent, of the total crude oil is, as will be evident from the report, 
richer in lighter terpenes. Because of the different conditions under 
which fractional distillation was carried out at the Imperial Institute 
it is not possible to compare the figures as obtained there with those 
obtained at Dehra or Pusa. But taking the figures worked out at 
the Imperial Institute as they are, it will be seen that only 33 per 
cent, of the tota] crude oil distilled with water passed at low 
temperatures (vide first report, Appendix D), about 66 per cent. pass, 
ing above 173° C., while the crude spirit distilled oil had 79—83 per 
cent, passing below 175° C. (vide second report, Appendix D), and the 
redistilled spirit distilled oil gave 89 per cent, passing below 175° C. 
These figures also conclusively show the improvement in quality 
that is effected by carrying the distillation at low temperatures with 
methylated spirit. No figures are available from the Imperial In¬ 
stitute allowing of comparison between the spirit or acetic acid dis¬ 
tilled oil and the crude or rectified water-distilled oil, yet the figures 
obtained at Dehra leave no doubt that the quality of the former is 
considerably purer. 
The report says that though the solvent power is inferior to the 
best oil obtainable in England, yet it can be used quite well for 
varnish making. 
Professor Dunstan recommends that trials of the process 
proposed should be made at the distillery to decide whether the 
[ 32 ] 
