300 ODOROGRAPHIA. 
“ One pikul of the dried plant just as it is cut yields from 24 to 
30 ounces of oil, and a sample free from the heavier stalks yields 
about double that amount. (Other records show the yield to 
vary between 15 and 4 per cent.) In an ordinary still (boiling 
the plant with water) not more than one half of the oil can be 
extracted, the temperature not being high enough to volatilize the 
whole of it *. 
“The green leaves yield little oil, therefore it is necessary that 
they be dried before distillation. 
“The oil is of two varieties, the one being sage-green, and the 
other the colour of medium-coloured sherry. It is thought that 
the green oil is produced from young leaves, and the golden-brown 
from old leaves ; but this is doubtful. Soil and shade may have 
more to do with the colour than the age of the leaves. Sometimes 
one colour is in greater demand than the other, but the prices are 
the same for both. The golden-brown oil has a sp. gr. of ‘9580 
at 85° F., and the green oil ‘9578 at the same temperature. 
“The spectrum exhibited by the golden-brown oil is not crossed 
by any absorption bands. The red, yellow, and green light, as 
far as the 4 line, are transmitted with full mtensity ; but the blue- 
green from J to F is much absorbed, and beyond the latter line all 
is complete darkness. The limits of this spectrum in wave-lengths 
are 7140 to 4165, the oil being contained in a tube ‘6 inch in 
diameter, both daylight and lamplight being used with the same 
results. 
“The green oil gives a spectrum of full intensity from the ¢ line 
to midway between 6 and F lines, from which point it shades off 
gradually and disappears a little before the / line is reached. At 
the red end it extends beyond the ¢ line, but with reduced inten- 
sity as far as to between the A and a lines. In wave-lengths the 
limits of this spectrum are 7390 to 4130 in daylight. Lamplight 
gave a greater extension towards the red end, but much less in the 
violet.” 
The following information respecting the cultivation of patchouli 
* This suggests that a finer quality could be separated by first distilling with 
water at ordinary pressure, and then extracting a second quality,—the portion 
with a higher boiling-point,—by passing steam of a certain pressure throagh the 
mass, and by carefully regulating the steam a third quality could be obtained, 
and the plant totally exhausted of oil. Operating in this way on leaves alone the 
first fraction of low boiling-point might be of very superior quality. 
