— 2 9 



Crude Japan camphor, examined according to these three methods, 

 gave the following values: 



i. Sublimation method: (mean of 4 tests, correction 2,77 °/ ); 

 content of camphor: 95,0 °/ , of non- volatile matter: o,i8°/ - 



2. Method of determination of specific gravity: 95,4 °/ (mean 

 of 3 tests). 



3. Polarisation method: 93,3% (mean of 4 tests). 



Judging from the m. p. 174 to 175,5°, tne sublimate must have 

 contained camphor oil, and for this reason the values obtained by 

 method 1 must come generally too high. The still higher value of 

 method 2 is explained by the fact that the specific gravity is influenced 

 not only by the oil, but also by the heavier water from the moisture. 

 This latter fact it was endeavoured to neutralise by recalculating the 

 values of the table for moist benzene, whose specific gravity was 

 determined at 0,8794 (dry 0,8782). Naturally, the quantity of water 

 absorbed by the benzene depended upon the temperature. The 

 determinations of specific gravity made with crude and pure camphor, 

 with due regard to the moisture, gave for the former a content of 

 106,9 an d 106,3 respectively, for the latter 101,4 and 100,2. 



The high values observed with pure camphor clearly show the 

 influence of the water on the density; for this reason the percentages 

 of the crude camphor must be divided by 1,066. In spite of this, 

 the mean of the values thus corrected, 94,5 °/ , remained too high, 

 proving thus the presence of camphor oil. 



An attempt to remove the impurities from the camphor according 

 to Forster's 1 ) directions, also remained without the desired result, 

 as was proved by the figures obtained; even tests made with pure 

 camphor led to losses of 2 to 3 °/ . 



The polarimetric method is least of all influenced by the presence 

 of impurities; the mean value obtained by this method is probably 

 not far from the actual camphor-content. The difference between 

 the results of the sublimation and polarisation methods should be taken 

 into account as camphor oil, so that crude camphor would have the 

 following composition: 93% camphor, 2 °/ camphor oil, 5°/ moisture, 

 o,i8°/ non-volatile substances. 



The analysis of synthetic camphor encountered difficulties. The 

 impurities of this product, intermediate products such as borneol, 

 camphene, etc. sublime jointly with the camphor, are also soluble in 

 benzene, and consequently increase the results of the methods 1 and 2. 

 Method 3 fails, as synthetic camphor is inactive; this method can 

 only be employed to differentiate between the natural and the synthetic 

 product. A crude synthetic camphor gave the following results: 



l ) Berl. Berichte 23 (1890), 2981. 



