28o 
Polarizing  without  a  Polarizer. 
{ 
Atn.  Jour.  Pharm. 
Jun-e,  1891. 
The  ferrous  salt  of  hypophosphorous  acid  is  not  stable,  almost  • 
immediately  changing  to  the  ferric  state  when  in  solution. 
On  the  following  type,  in  which  a  solution  of  ferrous  hypophos- 
phite,  prepared  by  double  decomposition  was  employed,  several 
trials  were  made  to  prepare  a  ferrous  syrup,  but  the  finished  pre- 
paration rapidly  decomposes. 
Ferrous  Sulphate  in  clear  crystals,  64  grs. 
Hypophosphite  of  calcium,  40  grs. 
Dissolve  the  calcium  and  iron  separately  in  one  ounce  of  hot 
water,  filter  and  allow  to  cool.  Gradually  mix  the  two  solutions, 
stirring  well,  filter  from  the  precipitated  calcium  sulphate,  and  add 
enough  water  through  the  filter  to  measure  3^  ounces. 
In  this  dissolve 
Hypophosphite  of  calcium,  180  grs. 
Use  5  grains  citric  acid  to  dissolve  all  the  lime,  filter  and  dis- 
solve the  sugar  by  agitation.  When  freshly  prepared,  this  is  of  a 
light  green  color  and  pleasant,  ferruginous  taste.  If  means  could 
be  found  to  stay  the  oxidation  of  the  ferrous  hypophosphite,  the 
syrup,  made  by  this  method,  would  be  no  doubt  a  most  satisfactory 
preparation.  None  of  the  methods  used  to  prevent  this  result, 
such  as  the  employment  of  heat  or  of  free  hypophosphorous  acid, 
was  however  successful. 
The  prevention  of  this  change,  the  addition  necessary  to  gain 
this  end,  presents  an  interesting  subject  for  future  research. 
Editor  American  Journal  of  Pharmacy. 
Sir  : — I  can  supplement  the  article  of  Dr.  Van  der  Weyde  (April 
number,  p.  182)  with  the  information,  due  to  Mr.  E.  W.  Sharp,  of 
this  city,  that  any  glazed  surface  will  polarize  the  light  sufficiently 
for  microscopical  purposes,  the  differences  observed  being  appar- 
ently due  to  the  color  of  the  reflector,  black  glass  being  undoubtedly 
the  best.  Incline  your  microscope  as  usual,  convenient  to  you  (the 
angle  probably  making  very  little  difference),  push  aside  (or  remove) 
the  mirror,  and  take  the  light  directly  from  the  reflecting  surface  ( 
for  instance,  the  polished  top  of  a  mahogany  table — even  a  small 
<  ( 
sodium,  . 
potassium, 
60  grs. 
60  grs. 
POLARIZING  WITHOUT  A  POLARIZER. 
