274 R, T. BAKER AND H. G. SMITH. 
a specific rotation — 2°52°. This probably accounts for the want 
of constancy in the rotation of the several oils from 2. punctata. 
The fractions boiling between 182-8 and 193-2° C. when mixed 
together were found to have no rotation. The redistillations of 
these oils were all made in asmall metal still holding about 130 ce. 
the outlet being 140 mm. above the surface of the oil, the bulb of 
the thermometer being just below this outlet. The heat was 
obtained from a small bunsen impinging on the bottom of the still 
and the whole enclosed in an outer casing of metal plate. It was 
possible to regulate the temperature with this arrangement 
accurately to one degree, between 170 and 180° C., by careful 
watching and regulation of the heat supply. The temperatures 
were corrected, 2:4° being added to the reading of 168° C., and 
2°8° to that of 180° O., and 3:2” to 190° C. 
5. The eucalyptol in the oils—The eucalyptol content of the oil 
is not constant unless the leaves are taken from the same tree. It 
is perhaps remarkable that the oils from Z. punctata that are the 
least coloured are the richest in eucalyptol, and as a rule they 
contain the greatest percentage of dextro-rotatory terpenes, and 
the amount obtained when redistilled coming over below 182°8° C. 
is greater than is the case with the darker oils. One oil, a very 
light one, gave 77 per cent. between 170°4 and 182°8° C. while 
another light oil gave 76 per cent. between 170-4 and 179°7° C. 
The percentage of eucalyptol is greater in the fraction boiling 
between 172-4 and 182-8° C. than in that distilling between 171°4 
and 182-8" C., as much as 15 per cent., distilling in some cases 
between 171:4 and 172°4°C. The percentage of eucalyptol ranges 
from 46-4 to 64-5 in the crude oils; one that gave 60-8 per cent. 
of eucalyptol gave a fraction boiling between 172:4 and 179:7° O. 
(60 per cent. of the whole) from which 78-5 per cent. of eucalyptol 
was obtained, while a crude oil giving 64:5 per cent. of eucalyptol 
gave a fraction between 171-4 and 182-8° C., from which 78°4 
per cent. of eucalyptol was obtained, the difference being accounted 
for by the presence of 15 per cent. boiling between 171:4 and 
172-4° C. in the latter oil. 
