256 
Distilled  Essence  of  Lemon. 
(  Am.  Jour.  Phanu. 
\      May,  1879. 
the  foreign  essence  did,  perhaps,  produce  a  more  favorable  impression^ 
but,  when  rubbed  in  the  hand,  as  the  fashion  of  the  expert  is,  the  fruity 
fragrance  of  the  distilled  oil  passed  out  of  comparison  with  anything 
the  imported  one  could  furnish.  The  odor  might  be  a  little  "thin" 
and  lacking  in  persistence,  but  superior  delicacy  was  manifest. 
Seeing  that  so  much  interest  was  excited  by  the  specimens,  some 
details  of  the  distillation  will  probably  not  be  unwelcome,  and  will 
afford  a  means  of  instituting  that  "comparison  of  the  operation  of 
obtaining  oil  of  lemons,  as  performed  by  Mr.  Moss  in  this  country, 
and  the  usual  operation  abroad,"  asked  for  by  Mr.  Giles  in  the  discus- 
sion previously  alluded  to. 
It  was  supposed  that  the  peel  of  600  lemons  would  yield  the  weight 
of  essence  required  by  Dr.  Tilden,  viz.,  eight  ounces,  and  that  quan- 
tity, weighing  forty-seven  pounds,  was  accordingly  operated  upon  as 
soon  as  received  into  the  laboratory.  It  was  placed  in  a  small  copper 
still  capable  of  holding  thirty  gallons,  covered  with  cold  water,  and  heat 
applied.  Twelve  gallons  of  liquid  were  distilled  over  into  an  earthen- 
ware receiver,  from  which,  when  the  oil  was  judged  to  have  separated^ 
the  water  was  run  off  below  into  a  similar  vessel.  The  oil,  not  quite 
free  from  water,  was  allowed  to  stand  in  a  separating  funnel,  and  when 
all  the  water  was  removed  measured  three  and  a  half  ounces.  This 
result  was  disappointing,  as  it  did  not  come  up  to  half  of  the  estimated 
yield.  No  more  oil  had  appeared  on  the  surface  of  the  separated 
water,  and  accordingly  ten  pounds  of  salt  were  dissolved  in  it,  with  the 
hope  that  a  further  slight  separation  might  be  promoted  thereby.  The 
expedient  was  futile,  though  the  solution  stood  over  night.  In  the 
morning  the  liquid,  salt  and  all,  was  returned  to  the  still,  from  which 
the  peel  had  not  yet  been  removed,  and  twelve  gallons  were  again 
drawn  over.     Not  a  single  drop  of  oil  was  obtained  from  this  distillate., 
It  was  therefore  necessary  to  operate  on  a  further  quantity  of  peel, 
and  this  time  fifty-two  pounds  were  taken;  for  practical  purposes,  the 
same  quantity  as  before,  viz.,  the  peel  of  600.  lemons.  In  this  opera- 
tion no  salt  was  used,  and  only  one  distillate  (twelve  gallons)  was  col- 
lected. The  yield  was  eight  and  a  half  fluidounces,  or  more  than 
twice  the  quantity  formerly  obtained.  Before  distilling,  however,  this- 
lot  of  peel  was  well  crushed,  and  the  cellular  tissue  torn  apart  to  free 
the  oil.  No  doubt  this  had  a  verv  important  influence  on  the  yield  of 
oil,  but  I  cannot  think  that  the  whole  of  the  gain  was  due  to  it,  espe- 
