44 
Polar imeter  and  its  Use, 
\m.  Jour.  Pharm 
Jan.,  1E80. 
The  resin  and  spirit  are  put  into  an  evaporating  dish  and  blended 
together  by  heating  over  a  water-bath,  then  poured  into  a  mortar  con- 
taining the  pulv.  tragacanth.  co.,  previously  made  into  a  thick  mucilage 
with  a  little  of  the  water,  and  rubbed  well  together,  the  syrup  and  the 
remainder  of  the  water  being  gradually  added. 
Reslnae  copaibae,  .  .  .  .    gr.  xv 
Tinct.  qiiillaige,  .  .  .    '  . 
Aq.  destillat.,     .  .  .  .  ad 
The  resin  is  dissolved  in  the  tincture,  and  the  water  gradually  added 
with  agitation. 
Bals.  Peru  ,  .  ...  .  .  rr^xv 
Tinct.  quillaise,  .  .  .  •  ,^i 
Aq.  destil.,  .  .  .  .  ad    5!  • 
This  mixture  is  open  to  the  same  objection — the  balsam  subsides  too 
rapidly.  The  above  quantity  of  balsam,  with  gr.  xv  of  pulv.  traga- 
canth. CO.,  gives  an  excellent  result. — Pharm.  'Journ.  and  Trans..  Sept. 
20,  1879. 
THE  POLARIMETER  AND  ITS  USE  IN  PHARMACY. 
By  Charles  Symes,  Ph.D. 
Read  before  the  British  Pharmaceutical  Conference. 
For  the  development  and  perfecting  of  the  science  and  practice  of  pharmacy  vari- 
ous instruments  and  forms  of  apparatus  have,  from  time  to  time,  been  introduced. 
It  is  not,  however,  to  a  new  instrument  that  I  am  desirous  of  directing  your  atten- 
tion, but  to  one  which,  although  it  came  into  existence  some  sixty  years  ago,  has  not 
in  this  country  and  in  recent  times  received  the  amount  of  attention  which  it  appears 
to  me  to  merit,  nor  has  it  been  applied  to  many  purposes  for  which  it  seems  calcu- 
lated to  be  of  u'^e. 
In  its  variously  modified  forms  it  is  known  as  the  polariscope,  saccharimeter,  polar- 
istrobometer  and  polarimeter,  men  of  science  and  manufacturers  having  progressively 
Introduced  such  alterations  as  appeared  desirable  for  the  better  accomplishment  of 
the  object  aimed  at,  viz.,  polarizing  a  ray  of  light  and  accurately  measuring  the 
amount  of  rotation  produced  in  that  ray  when  it  is  passed  through  an  optically  active 
'liquid  or  liquid  possessing  rotatory  power.  My  chief  aim  in  bringing  this  subject 
before  the  members  of  the  Conference  is  to  offer  for  their  consideration  some  of  my 
•experience,  and  to  render  familiar,  as  far  as  I  am  capable  of  so  doing,  this  instru- 
ment which  has  hitherto  been  dealt  with  chiefly  in  works  of  a  purely  scientific  char- 
acter, and  which  has  been  regarded  by  the  working  pharmacist  as  outside  his  pro- 
vince, and  useful  only  in  the  prosecution  of  abstract  science.  That  too  little  is 
known  of  its  general  application  has  long  been  my  opinion;  but  this  was  brought 
more  forcibly  to  my  mind  in  June  of  last  year,  when  (in  company  with  Mr.  Green- 
ash)  I  paid  a  short  visit  to  M.  Petit,  of  Paris,  and  found  him  using  the  instrument  of 
