392 
STRENGTH  OF  COMMERCIAL  ALCOHOL. 
of  90  per  cent,  is  equal  to  190  proof;  100  of  70  per  cent,  to 
1T0  proof,  and  so  on,)  proof  spirit  being  equal  parts  by  measure 
of  pure  alcohol  and  water. 
Now  take  Mr.  Mead's  statement;  he  says  "  he  bought  his  alco- 
hol for  80  per  cent,  and  found  it  to  be  sp.  gr.  0-834,  which  would 
be  nearly  85  per  cent,  by  weight,  and  90  per  cent,  by  volume." 
If  it  was  80  per  cent,  (according  to  the  distiller's  scale)  100 
gallons  of  that  alcohol  would  make  180  gallons  of  proof  spirit; 
now  proof  being  equal  parts  of  pure  alcohol  and  water,  it  would 
be  composed  of  just  90  gallons  of  pure  alcohol  and  90  gallons 
of  water;  therefore  the  alcohol  which  he  purchased  would  contain 
90  gallons  of  pure  alcohol  in  100  gallons,  or  in  other  words  it 
would  be  just  90  per  cent,  by  volume,  or  about  85  per  cent,  by 
weight,  which  will  correspond  with  his  and  my  own  experiments. 
If  the  distiller's  scale  is  as  I  state  it,  am  I  right  in  my  con- 
clusions ?  If  I  am,  and  if  it  is  a  rare  thing  to  find  it  elsewhere, 
our  distillers  deserve  credit  for  making  their  alcohol  so  near  the 
standard  laid  down  in  the  U.  S.  Pharmacopoeia,  which  is  sp.  gr. 
0«835  or  85  per  cent,  by  weight. 
I  do  not  know  the  fact,  but  infer  from  the  statement  of  the 
distillers,  that  the  hydrometer  used  by  them  is  Sike's,  or  one  of 
similar  construction,  and  that  perhaps  it  may  more  properly  be 
said  to  be  80  per  cent,  over  proof  . 
I  see  that  Mr.  Gutteridge,  in  his  tables,  would  give  the  sp.  gr. 
0*835  to  be  very  near  57  per  cent,  over  proof,  but  Pereira  in  the 
article  on  alcoholometry  says  that  Mr.  Gutteridge's  statement 
does  not  coincide  with  experiments  which  he  has  made  on  the 
same  subject. 
I  was  much  pleased  with  the  remarks  of  Mr.  Pile  on  the  dif- 
ference in  hydrometers,  as  it  explains  to  me  what  I  have  been 
trying  without  success  to  solve.  I  purchased  of  Mr.  J.  Wight- 
man,  Boston,  one  of  Luhme  &  Co.'s  alcoholometers,  graduated  by 
Tralles  &  Richter's  scales;  after  taking  it  home,  I  tried  it  with 
some  alcohol,  to  see  how  it  agreed  with  the  tables  in  Wood  & 
Bache's  Dispensatory,  and  to  my  surprise  it  gave  a  different  result. 
Then  to  determine  if  either  was  correct,  I  took  it  to  the  Custom 
House,  and  through  the  kindness  of  Mr.  Lewis  tested  it  with 
their's,  (supposing  I  could  depend  upon  their's  as  a  standard  in- 
strument, it  being  made  expressly  for  Government  use ;)  the 
