76         NOTES  ON  LEMON-JUICE  AND  ITS  DECOMPOSITION. 
passed  by  an  officer  appointed  by  the  Board  for  that  purpose. 
It  is  to  be  tested  for  gum,  sugar,  citric  acid,  and  general  freedom 
from  adulteration.  It  is  to  have  a  specific  gravity  of  not  less 
than  1*030  and  not  less  than  30  grs.  of  citric  acid  per  ounce, 
and  to  have  a  proper  taste,  color,  odor,  and  consistence.  The 
consternation  among  the  merchants  holding  large  quantities  of 
lemon-juice  may  easily  be  imagined,  for  although  the  Board  of 
Trade  has  given  considerable  latitude  in  their  requirements,  yet 
hardly  any  in  the  market  would  stand  the  tests,  and  pass  the  ex- 
amining officer.  Not  an  ounce  of  genuine  juice  was  to  be  bought 
in  Liverpool,  Birmingham,  or  Bristol. 
This  then  being  the  case,  naturally  led  to  a  great  many  analy- 
ses of  samples  from  various  quarters.  The  author  was  thus 
attracted  to  the  present  subject  by  the  wide  discrepancy  between 
the  result  of  his  experiments,  and  the  information  published  in 
our  best  books. 
For  instance,  Pereira  gives  an  analysis  of  lemon-juice  by 
Proust,  showing  that  it  contained  1*77  per  cent,  of  citric  acid, 
or  about  10  grains  per  ounce.  The  specific  gravity  is  not  men- 
tioned. It  is  surprising  that  the  statement  should  have  been 
introduced  into  the  last  edition  of  that  work.  In  our  excellent 
British  Pharmacopceia,  freshly  pressed  lemon-jmce  is  said  to  have 
an  average  specific  gravity  of  1-039,  and  an  average  quantity  of 
32-5  grains  of  citric  acid  per  ounce.  These  two  do  not  agree  ; 
the  specific  gravity  is  too  great  for  the  acid.    In  Muspratt's  ^ 
Dictionary,"  juice  containing  seven  per  cent,  or  31*5  grains 
per  ounce,  is  termed  very  superior.  In  Mr.  Watt's  splendid 
work,  4*7  per  cent,  or  201  grains  per  ounce  is  quoted  as  the 
amount.  Muspratt  says  that  lemons  at  an  earlier  part  of  the 
season  are  more  acid,  and  as  the  season  advances  the  water  is  a 
percentage  or  two  higher.  All  these  statements  are  so  greatly 
at  variance  with  the  results  I  have  found,  that  I  am  induced  to 
bring  the  subject  before  the  Conference. 
As  will  be  seen,  the  Board  of  Trade  have  fixed  very  liberally 
for  the  vendors  the  specific  gravity  of  1*030  as  the  standard, 
and  30  grains  per  ounce  as  the  least  quantity  of  acid. 
On  February  25th  of  this  year  I  bought  a  lot  of  lemons  from 
six  difierent  shops,  and  after  mixing  them,  I  pressed  eight,  which 
