CRYSTALLINE CAMPHOR OF EUCALYPTUS OIL. 97 



acid (crystallises out again on adding water), acetone, benzene, 

 olive oil and oils generally. The volatile solvents all leave the 

 eudesmol in a crystalline condition on evaporation, either at once 

 or crystallisation soon takes place on standing. 



Melting Point. 



Perfectly purified eudesmol melts at 79 - 80° C. The crystal- 

 lised substance from dilute alcohol, from acetic acid, and the 

 sublimed material, all melted at that temperature, and by no 

 method of purification was 80° C. exceeded. The tendency to 

 give lower melting points was most troublesome, necessitating 

 many scores of determinations on different material. Minute 

 portions of the high boiling terpenes are prone to be retained, and 

 these lower the melting point considerably. The best method of 

 taking the melting point was found to be as follows : — the camphor 

 was melted at the lowest possible temperature, and a portion drawn 

 into a capillary tube and allowed to perfectly crystallise again in 

 the tube; 3 mm. of the column was then retained; the tube was 

 attached to the thermometer and suspended in water which was 

 slowly heated. The substance was considered to have reached its 

 melting point at the instant when it began to rise in the tube. 



Sublimation. 



Purified eudesmol, melting at 79 - 80° 0. was taken. This 

 sublimed readily, care being taken to keep the upper glass cool ; 

 fine crystals of a good length were obtained. Is was found that 

 when the sublimation was carried out at the lowest possible 

 temperature, that the sublimate melted at the same temperature 

 as at first, but that if heated too much, the melting point of the 

 sublimate had been lowered ; this was found to be the case under 

 all conditions, the tendency being to form substances having a 

 lower melting point. Sublimation takes place at a little above 

 100° C; a distinct sublimate was obtained by heating in a tube 

 closed at one end when suspended in boiling water for some time. 



The melting point of the sublimate being lowered by overheat- 

 ing, an attempt was made to determine at what temperature this 

 decomposition commenced. A small U tube was taken with one 



G-Aug. 2, 1899. 



