104  PREPARATION  OF  HEAVY  OIL  OF  WINE. 
In  25  days,  forty- two  distillations  were  made,  and  2055  lbs. 
sulphuric  acid  and  137  gallons  of  strong  alcohol  used.  The 
yield  was  288  oz.  of  heavy  oil  of  wine  ;  the  specific  gravity  was 
taken  with  a  hydrometer,  but  no  correction  was  made  for  the 
difference  in  temperature,  of  which  no  record  was  kept.  The 
above  quantity  of  alcohol  weighs  932*7  lbs.,  and  one  ounce  of 
heavy  oil  of  wine  was  therefore  produced  from  114*16  oz.  sul- 
phuric acid  and  51*82  oz.  avoirdupois  of  alcohol,  which  makes 
very  nearly  2  per  cent,  of  the  latter. 
The  table  appended  to  Mr.  Diehl's  paper  may  now  be  ex- 
tended as  follows : 
Dr.  E.  R.  Squibb.  C.  Lewis  Diehl,  Jr.,  at 
U.  S.  A.  Laboratory. 
1st  series.         2d  series. 
Sulphuric  acid  required  to  make 
oue  avoird.  oz  of  oil  of  wine,  173  av.  oz.  157  av.  oz.  114-16  av.  oz. 
Alcohol  required  for  the  same,  111       "         71-77"         51-82  " 
Average  yield  from  each  distillation,     4-54  "  5-52  "  6-86  u 
If  we  examine  the  temperatures  in  Mr.  Diehl's  table,  it  will 
be  observed  that  large  yields  were  always  obtained  where  the 
temperature  was  steadily  kept  between  about  302  and  315°  F. 
His  largest  yields  were  Nos.  18,  28,  and  37,  furnishing  one  oz. 
of  oil  of  wine  for  49  to  50J  fluidounces  of  alcohol.  With  five 
re-heatings,  the  temperature  was  steadily  between  302  and  315; 
rising  in  the  first  instance,  towards  the  close,  to  316,  and  in 
both  the  other  cases  attaining  the  temperature  of  317  at  the 
beginning  of  the  process. 
The  second  best  yields,  requiring  52  to  53  fluidounces  of 
alcohol  for  one  ounce  of  oil,  were  Nos.  24  and  27.  In  the 
former  the  temperature  rose  at  first  to  319,  but  was  subsequently 
kept  between  301  and  312 ;  No.  27  was  kept  between  302  and 
314,  rising  only  towards  the  close  to  318°. 
On  the  other  hand,  it  will  be  observed,  that  where  he  ob- 
tained small  yields,  the  temperature  either  rose  considerably 
and  frequently  above  315,  or  fell  below  302.  Thus,  of  the 
distillations  yielding  one  ounce  of  oil  of  wine  for  75  and  78 
fluidounces  of  alcohol,  the  temperature  rose  in  No.  42  to  324, 
and  in  No.  33  to  321°.  In  No.  22,  yielding  one  ounce  of  oil 
from  64  fluidounces  of  alcohol,  the  temperature  fell  to  282° ; 
in  Nos.  2  and  9,  it  fell  to  298°,  and  the  yield  was  one  ounce 
from  66  to  67  fluidounces  of  alcohol.    The  only  case  in  which 
