1 82  Polarization  without  a  Polarizer.  {Aa\lprn,mirm' 
acid  the  odor  of  acetic  acid  is  evolved  or  if  an  addition  of  alcohol  is 
previously  made,  that  of  acetic  ether. 
Alkaloids,  especially  caffeine,  which  was  at  first  suspected,  were 
not  found,  no  reagents  giving  any  indication. 
We  may  sum  up  the  compound  to  have  about  the  following 
composition  : 
Antifebrin  or  acetanilid,  47  parts. 
Bicarbonate  of  sodium,  50  " 
Tartaric  acid   3  " 
Incidentally  may  be  mentioned,  that  the  mixture  can  be  prepared 
for  about  10  cents  per  ounce,  for  which  the  manufacturers  charge 
$MO.  
<      POLARIZATION  WITHOUT  A  POLARIZER. 
By  P.  H.  Van  der  Weyde,  M.D. 
To  the  Editor  of  the  American  Journal  of  Pharmacy  : 
Under  this  heading,  Mr.  H.  M.  Wilder  published  in  The  Ameri- 
can Journal  of  Pharmacy  the  announcement  that  he"  accidentally 
made  a  quite  useful  discovery."  It  appears  that  the  study  of  one 
of  the  most  interesting  branches  of  physics,  the  polarization  of 
light,  has  thus  far  been  lamentably  neglected,  as  proved  by  the  fact 
that  this  announcement  is  now  going  round  the  press  without 
remark  or  comment  (see  Scientific  American  Supplement,  No.  793, 
and  other  scientific  papers)  wherefore  I  may  be  allowed  to  give  to 
your  readers  the  following  items  of  information. 
The  discovery  that  certain  regions  of  the  atmosphere  polarize 
the  sunlight  was  made  by  Arago  in  1809;  he  went  further,  and 
determined  the  regions  of  maximum  and  minimum  polarization,  the 
latter  he  found  1  iy2°  above  the  sun  a  little  before  sunrise  and  a  little 
time  afier  sunset,  and  also  n}4°  above  the  opposite  point  of  the 
heavens,  while'  the  maximum  polarization  takes  place  in  a  circle  or 
belt  situated  exactly  900  from  the  sun  as  centre. 
As  the  position  of  this  polarized  circle  of  light  is  continually 
shifting  with  the  position  of  the  sun,  and  is  only  sufficient  for  prac- 
tical purposes  when  the  mirror  of  the  microscope  reflects  the  light 
from  this  belt,  microscopists  found  difficulty  to  obtain  sufficient  light 
from  it,  and  it  never  came  in  use ;  in  consequence,  it  appears  at  pres- 
ent to  be  entirely  forgotten. 
As  soon  as  I  came  in  possession  of  a  polarizing  microscope,  50 
