188 
Production  of  Lemon-Grass  Oil.    {  Am'2££h  ?w.m' 
Upper  portion,  74  per  cent. ;  lower  portion,  76  per  cent.  These 
results  show  that  the  closest  cutting  which  gives  a  profitable  yield 
of  oil  also  produces  a  better  quality  of  oil. 
Soil  Moisture. — Plants  of  variety  No.  1,  grown  on  soils  having 
varying  degrees  of  moisture,  yielded  oil  with  citral  content  as 
follows :  On  dry  sandy  soil,  75  per  cent,  citral ;  on  slightly  moist 
sandy  loam,  68  per  cent. ;  and  on  moist  loam  near  the  lake,  66  per 
cent.  Further  tests  with  other  varieties  on  different  types  of  soil 
have  given  similar  results.  This  would  indicate  that  high  citral 
content  can  be  secured  only  from  plants  grown  on  very  well  drained 
soil. 
Time  of  Harvest. — Although  the  citral  content  of  the  oil  does 
not  appear  to  be  greatly  affected  by  the  time  of  harvest,  the  results 
indicate  that  of  the  two  harvests  each  year  the  oil  distilled  from 
plants  of  the  first  harvest  contains  the  greater  quantity  of  citral. 
Data  covering  a  number  of  years  are  given  in  Table  V. 
Table  V. 
Citral  Content  of  Lemon-grass  Oil  Distilled  from  Plants  Harvested  at  Two 
Different  Times  of  the  Year. 
Citral  Content  of  Oil. 
First 
Harvest. 
Per  Cent. 
72 
74 
75 
76 
78 
78 
78 
77 
Second 
Harvest. 
Per  Cent. 
74 
72 
72 
78 
76 
76 
79 
Year  and  Plants 
Harvested. 
1914  —  Continued 
No.  8  
No.  9  
1915. 
No.  5  
No.  6  
No.  8  
No.  9  
No.  10  
No.  11  
No.  12  
No.  13  
Citral  Content  of  Oil. 
First 
Harvest. 
Per  Cent. 
81 
75 
70 
73 
77 
78 
80 
80 
81 
85 
SOLUBILITY  OF  LEMON-GRASS  OIL  IN  ALCOHOL. 
For  many  years  it  was  considered  that  good  lemon-grass  oil 
should  be  soluble  in  clear  solution  in  three  volumes  of  70  per  cent, 
alcohol,  and  this  was  the  test  applied  before  the  method  of  citral 
determination  was  in  general  use.  It  served  a  useful  purpose,  how- 
ever, inasmuch  as  certain  adulterations  which  had  become  quite 
