''^"j^nr'issS™'}  ^^Gohol  Tables  of  the  New  Pharmacopceia.  303 
ALCOHOL  TABLES  OF  THE  NEW  PHARMACOPCEIA. 
By  Gustavus  Pile. 
Head  at  the  Pharmaceutical  Meeting^  May  15,  1883. 
The  comprehensive  specific  gravity  tables,  indicating  the  percentage 
of  alcohol,  that  have  been  placed  in  the  New  Pharmacopoeia,  are,  no 
doubt,  the  result  of  considerable  time  and  labor,  yet  it  cannot  but  cause 
a  feeling  of  disappointment  to  find  the  familiar  tables  of  Tralles  super- 
seded by  those  of  Helmer.  In  this  country,  universal  custom  as  well 
as  legal  authority,  have  for  so  long  a  time  endorsed  Tralles  as  the  stand- 
ard, that  he  should  not  have  been  supplanted  by  any  other  without 
very  positive  knowledge  of  inaccuracy.  The  want  of  legalized  stand- 
ards for  defining  the  commercial  value  of  chemical  products  is  seriously 
felt  in  many  instances,  in  order  to  prevent  misunderstanding  and  con- 
troversy, yet  in  this  case  where  such  authority  does  exist,  we  find  our 
long  used  tables  set  aside  for  others  whose  superiority  lies  merely  in 
the  fact  of  their  completeness.  But  why  not  compile  just  such  tables 
having  Tralles  for  a  basis,  and  thus  keep  in  liarmony  with  law  and 
custom  ?  Besides  this,  the  tables  of  Hehner  do  not  possess  the  quality 
of  accuracy  to  an  extent  to  merit  our  confidence.  I  have  not  had 
sufficient  time  to  examine  the  subject  fully,  but  there  appears  to  be 
considerable  variation  from  what  has  long  been  regarded  as  reliable 
rstatements.  Hehner  began  his  tables  by  denoting  the  specific  gravity 
of  water  as  1*000  at  60°F.,  and  compared  the  gravities  of  the  percent- 
ages of  alcohol  with  it,  that  is  at  the  start,  but  at  the  end  we  find  abso- 
lute alcohol  indicated  by  a  specific  gravity  of  '7938,  which  is  the  case 
when  compared  with  water  as  unity  at  39°F.,  but  when  water  is  taken 
as  unity  at  60°F.  as  he  began,  it  should  be  represented  by  •7946.  So 
we  have  in  these  tables  two  different  values  used  to  denote  the  specific 
gravity  of  water  as  a  standard,  one  at  the  beginning  and  another  at 
the  end. 
The  law  of  the  United  States  defining  the  term  proof  spirit,  is  so 
very  decided,  that  it  seems  strange  indeed  that  any  other  should  be 
given  in  a  Avork  purporting  to  be  a  national  standard.  According  to 
Revised  Statute  3249,  the  law  reads  as  follows  :  "  Proof  spirit  shall 
be  held  and  taken  to  be  that  alcoholic  liquor  which  contains  one-half 
its  volume  of  alcohol  of  a  specific  gravity  of  '7939  at  60°  Fahr., 
referred  to  water  as  its  maximum  density  as  unity."  Proof  spirit  has 
Sit  60°  Fahr.  a  specific  gravity  of  '93353,  100  parts  by  volume  of 
