456 R. ROBINSON AND H. G. SMITH. 
so obtained in colourless prismatic needles. When not 
quite pure, eudesmin occasionally crystallises in the form 
of leaflets. The melting point of pure eudesmin is 107° and 
although the molecule is large, small quantities of the sub- 
stance may be distilled unchanged in vacuo. The substance 
is levo-rotatory and the following determinations have 
been made :— 
1°3112 made up to 100 ccm. with chloroform at 21° gave 
[a]> = -—64°4 
1°0022 made up to 10 ccm. with chloroform, 
[a]> = —64°3° 
1°0834 made up to 10 ccm. with benzene, 
lalp = —92°3° 
1°0294 made up to 10 ccm. with acetic acid, 
la), = —i373° 
The first two determinations were made with distinct 
specimens of eudesmin and with different instruments, so 
that the rotation in chloroform is a physical constant, the 
determination of which will be of great value in proving 
the identity of eudesmin derived from different sources. 
The following analyses of eudesmin have been performed: 
0°1224 gave 0°3051 CO, and 0°0763 H.O. C=68°0; H=6°9. 
0°1206 gave 0°3018 CO, and 0°0718 H,O. C=68'°2; H=6°6. 
0°1211 gave 0°3028 CO, and 0°0730 H.O. C=68°2; H=6°7. 
1°1972 dissolved in 77°504 benzene gave a solution whose 
freezing point was ‘193° lower than that of benzene. 
Whence M.W. = 392. C2reH2eO¢ requires O = 68°4, H = 6°7 
per cent., and M.W. = 386. 
The methoxy groups were determined by Zeisel’s method: 
0°1400 gave 0°3417 AgIl. MeO = 32°2. CooHoeO¢ containing 
4 MeO requires MeO = 32’1 per cent. 
Eudesmin dissolves in sulphuric acid to a red solution 
which slowly becomes purple, this latter change is how- 
