BULLETIN 442, U 
DEPARTMENT OF AGRICULTURE. 
charge. Drying the plants seems to have no effect on the citral 
content of the oil, but on storing it was found that the solubility of 
the oil in alcohol diminished more rapidly in the oils from the dried 
material. 
Table II. — Yield and citral content of lemon-grass oils distilled from green and from 
dried plants. 
Condition of material. 
Weight of 
material 
(green). 
Weight of 
material 
(dried). 
Yield of 
oil (based 
on green 
weight of 
material). 
Citral con- 
tent of 
the oil. 
Fre<h - 
Pounds. 
78.1 
93.1 
100.3 
Pou rids. 
Per c(nt. 
0.37 
.31 
.32 
Per C( nt. 
7-. 
58. 3 
iV2. 7 
7s 
Artificially dried 
79 
DISTILLATION. 
The apparatus required for the distillation of lemon-grass oil does 
not differ from that in general use for the distillation of other volatile 
oils. Before distilling the plants it has been found advisable to run 
them through a fodder cutter, in order to permit closer packing in the 
retort. From the data at hand it is estimated that if the plants are 
cut into 2-inch lengths a retort will hold 100 pounds of material for 
every 6 cubic feet of space, but if the plants are put in whole the 
quantity which the retort can hold will be somewhat less. The 
closer packing, however, in no way facilitates distillation. 
In a retort having a capacity of 30 cubic feet a charge of 3,000 
pounds can be distilled in 2 to 2 -J hours by the steam which may be 
readily generated in a small farm boiler, and by the use of a larger 
volume of steam the time can be much reduced. 
In this connection it is interesting to note that distillation under 
20 pounds pressure in the retort increased the yield of oil, but gave 
an oil of very dark color and with lower citral content. 
After the oil has been distilled it should be freed from water so far 
as possible in a separatory funnel, then dried by shaking with anhy- 
drous calcium chlorid, and filtered. It should be stored in well-filled 
air-tight containers in as cold a place as possible until ready to be 
shipped to market. The shipping can be done in new and clean tin 
cans without injury to the product. 
In order to determine whether any appreciable quantity of oil 
would be lost by discarding the distilled water coming over with the 
oil, a series of tests was made in 1915. The water from a number of 
charges of several pounds each was retained and each lot separately 
redistilled. In the apparatus used in the experiments about 1 
gallon of water was secured for each 22 pounds of herb in the charge. 
The average of the results secured by the redistillation of this water 
