586  Minutes  of  the  Pharmaceutical  Meeting.  {AmNoZ'm9&Tm' 
sparingly  soluble  potassium  salt.  When  iodine  is  added  to  a  solu^ 
tion  of  sodium  thiosulphate  containing  a  sufficient  quantity  of  potas- 
sium iodide,  potassium  tetrathionate  is  alone  formed. 
The  compound  KAgS203+NH3  separates  in  nacreous  plates  when  a 
solution  of  either  of  the  sodium  potassium  thiosulphates,  or  of  potas- 
sium thiosulphate,  is  mixed  with  an  equivalent  quantity  of  an  ammoniacal 
silver  nitrate  solution.  It  is  very  sparingly  soluble  in  water,  and  silver 
sulphide  quickly  separates  from  the  solution,  but  it  dissolves  freely 
in  hot  ammonia,  and  crystallizes  from  the  cold  solution  in  large  plates. 
It  is  stable  at  the  ordinary  temperature,  but  at  100°  ammonia 
is  evolved  and  a  gray  powder  remains.  When  a  solution  of  sodium 
thiosulphate  is  mixed  with  ammoniacal  silver  nitrate,  no  precipitation 
occurs,  but,  on  adding  potassium  chloride  or  potassium  nitrate,  the 
compound  just  described  separates  in  nacreous  plates. 
Sodium  silver  thiosulphate,  NaAgS203+H20,  is  obtained  in  large, 
well-defined,  monoclinic  plates,  when  a  solution  of  equivalent  quan_ 
tities  of  sodium  thiosulphate  and  ammoniacal  silver  nitrate  is  evap- 
orated over  sulphuric  acid  (compare  Lenz,  Annalen,  Ix,  94).  It 
decomposes  only  slowly  at  the  ordinary  temperature,  but  immedi- 
ately on  heating  ;  at  100°  only  water  is  evolved,  and  a  gray  crys- 
talline powder  remains.  It  is  very  sparingly  soluble  in  water,  and 
the  solution  is  unstable,  but  it  dissolves  freely  in  cold  ammonia, 
and  on  adding  alcohol  a  colorless  flocculent  compound,  probably 
NaAgS203+NH3,  is  precipitated. 
It  follows  from  the  above  experiments  that  both  sulphites  and  thio- 
sulphates have  an  asymmetrical  constitution. 
MINUTES  OF  THE  PHARMACEUTICAL  MEETING. 
October  15th,  1889. 
The  meeting  was  called  to  order  and  on  motion  Mr.  Wm.  B.  Webb  was- 
called  to  preside,  and  the  reading  of  the  minutes  was  dispensed  with. 
The  Registrar  stated  that  Mr.  Good,  a  manufacturer  of  specialties  in  which  tar 
was  a  component,  had  sent  to  the  College  specimen  cans  in  which  he  was  in 
the  habit  of  putting  up  tar  for  the  trade,  and  also  an  open  glass  jar  containing 
some  of  the  tar  such  as  was  put  up  in  cans.  The  thanks  of  the  College  were 
tendered  him  for  the  same. 
The  Registrar  stated  that  since  the  last  meeting  Professor  Maisch  bad  pre- 
sented a  copy  of  Buchner's  Repertorium,  a  periodical  formerly  published  in  Ger- 
many, in  one  hundred  and  ten  volumes,  presenting  a  very  complete  history  of 
pharmaceutical  science  during  the  time  of  its  publication  ;  these  with  some 
