566 
Official  Lead  Preparations. 
( Am.  Jour.  Pharm. 
\  November,  1897. 
ket,  to  employ  it  with  any  degree  of  confidence  for  the  accurate 
determination  of  the  specific  gravity  of  Goulard's  extract. 
The  results  of  the  writer,  pertaining  to  the  quality  of  commercial 
lead  acetate,  will  be  treated  of  subsequently. 
At  the  suggestion  of  Prof.  H.  Trimble,  the  writer  prepared  lead 
acetate  from  a  sample  of  litharge,  which  assayed  99  per  cent,  of 
lead  oxide,  crystallizing  the  salt  from  a  slightly  acid  solution. 
The  air-dried  salt  was  obtained  in  silky  masses,  considerably  more 
bulky  than  the  commercial  salt. 
Goulard's  extract  was  prepared  from  this  salt. 
For  the  accurate  determination  of  the  specific  gravity  maceration 
was  first  employed,  each  step  in  the  process  being  carefully  checked 
and  every  precaution  observed. 
About  1  litre  of  distilled  water  was  heated  to  boiling,  and,  while 
hot,  poured  into  a  previously  sterilized  bottle  and  allowed  to  cool. 
730  c.c.  of  the  water  were  measured  out  and,  to  determine  the 
exact  quantity,  weighed. 
To  further  prove,  the  amount  was  calculated  to  troy  weight,  and 
compared. 
170  grammes  of  the  acetate  were  dissolved  in  the  water,  and  to 
this  solution  100  grammes  of  the  99  per  cent,  lead  oxide  were 
added  in  divided  portions. 
The  mixture  was  allowed  to  stand  in  a  well-closed  bottle  for  five 
days,  agitating  repeatedly,  at  the  expiration  of  which  time  the  mix- 
ture was  again  weighed  and  no  loss  noticed. 
It  was  then  filtered  with  the  usual  precautions. 
The  specific  gravity  of  the  finished  solution  was  found  to  be 
fi 
1-230,  and   13  67  grammes  required  between  25  and  26  c.c.  of  — 
H2S04  for  complete  precipitation,  using  methyl-orange  as  indicator. 
To  verify  the  above  result  the  solution  was  prepared  by  the  phar- 
macopceial  process,  with  scrupulous  observation  of  all  details,  em- 
ploying the  same  salts  as  in  the  foregoing  operation. 
The  specific  gravity  of  this  solution  was  1-229,  and  13*67  grammes 
also  required  between  25  and  26  c.c.  of  the  normal  acid  for  precipi- 
tation, thus  obtaining  almost  identical  results. 
Various  similar  experiments  were  also  made  with  acetates  and 
oxides  of  lower  percentage  than  employed  in  the  foregoing.  The 
results  thus  obtained  were  deemed  of  importance,  as  the  lead  acetate 
