EPSOM  SALT!  IN  CITRATE  OP  MAGNESIA  SOLUTION.  397 
There  is  an  important  reason  for  not  putting  the  soap  in  the 
room  of  higher  temperature  at  first,  for  it  would  then  melt,  in- 
stead of  drying  properly,  and  become  unmanageable.  The  pow- 
der from  the  first  experiment  was  fine,  light,  and  very  white ; 
that  from  the  second  was  not  so  white,  owing,  probably,  to  the 
fact  of  its  being  kept  a  greater  length  of  time  and  the  presence 
of  a  little  sesquioxide  of  iron,  the  color  of  the  iron  being  masked 
when  the  soap  was  fresh,  as  in  the  first  experiment,  the  iron  being 
then  in  the  state  of  protoxide  ;  21  cents  per  lb.  was  paid  for  the 
white  soap  (in  Exp.  1)  which  was  a  low  figure,  (Feb.,  1867),  and 
as  the  loss  was  27*28  per  cent.,  allowing  12  cents  per  lb.  for 
powdering,  the  lowest  cost  of  the  powder  would  be  88  cents,  and 
yet  a  powdered  white  Castile  can  be  bought  for  that  price  ;  the 
inference  regarding  the  character  of  such  a  powder  is  of  course 
unmistakable.  It  would  be  an  easy  task  for  the  Pharmacist  to 
prepare  his  own  powdered  soap,  the  only  necessary  outlay 
would  be  for  that  unscientific  instrument,  the  cabbage  cutter, 
which,  however,  could  be  used  with  advantage  in  making  tinct. 
sapon.  camph.,  opodeldoc,  soap  plaster,  &c,  not  to  speak  of  its 
legitimate  use  ;  for  small  operations  the  soap  could  be  shaved  with 
a  spatula.  If  a  drying  room  is  not  at  command,  the  difficulty  of 
drying  it  thoroughly  may  be  overcome  by  shaving  the  soap  very 
thin,  then  spreading  on  paper  and  setting  in  a  warm  place  ;  the 
drying  of  course  is  hastened  by  a  current  of  air.  After  it  be- 
comes dry  and  friable,  it  can  be  easily  powdered  in  a  mortar  and 
sifted  through  a  fine  sieve,  and  the  Pharmacist  has  then  the 
satisfaction  of  saving  the  difference  in  the  cost  of  powdering  and 
of  furthering  the  cause  of  "Medicine  Puritas." 
ON  EPSOM  SALT  IN  CITRATE  OF  MAGNESIA  SOLUTION. 
By  William  R.  Warner,  of  Philadelphia. 
Much  of  late  has  been  written  on  Citrate  of  Magnesia,  but  no 
very  definite  or  satisfactory  data  have  been  arrived  at,  whereby  the 
difficulty  of  obtaining  an  uniformly  permanent  solution  has  been 
overcome  and  a  desirable  result  attained.  Much  improvement, 
however,  in  the  construction  of  the  formula  has  been  made  ;  the 
same  being  made  easy  of  manipulation  over  the  old  receipt  of 
