ioo  Solubility  of  Iodine  in  Chloroform.  {A%Je0b%™arm* 
or  such  quantity  of  the  substance  to  be  examined  as  will  give  that 
quantity,  is  weighed  out  and  dissolved  in  alcohol,  an  excess  of 
alcoholic  soda  is  added,  and  after  about  ten  minutes'  digestion  near 
the  boiling  point  of  the  alcohol,  the  excess  of  alcohol  is  evaporated  ; 
the  residue  is  taken  up  with  water,  made  slightly  acid  with  dilute 
nitric  acid  and  a  small  quantity  of  calcium  carbonate  added  to 
restore  neutrality.  The  solution  is  then  titrated  with  the  solution 
of  nitrate  of  silver  used  for  water  analysis  (of  which  I  cc.  =  -005418 
gram  iodoform);  an  excess  of  about  -3  cc.  is  required  to  produce  a 
good  end  reaction  with  chromate  of  potash,  and  this  should  be 
subtracted. 
SOLUBILITY  OF  IODINE  IN  CHLOROFORM. 
By  W.  Duncan. 
Some  time  ago  I  had  occasion  to  prepare  a  solution  of  iodine  in 
chloroform.  The  difficulty  I  had  in  getting  the  required  amount 
into  solution  brought  to  my  recollection  a  remark  of  one  of  my 
students,  to  the  effect  that  he  had  found  it  impossible  to  make  a 
solution  stronger  than  about  I  grain  of  iodine  in  each  drachm  of 
chloroform. 
On  referring  to  standard  works  I  found  that,  with  one  exception, 
those  which  refer  to  the  point  state  that  iodine  is  freely  soluble  in 
chloroform.  The  exception  is  Squire's  "  Companion,"  in  which  the 
solubility  is  given  as  1  in  25.  I  have  utterly  failed  to  obtain  a 
solution  of  this  strength,  and,  for  my  own  satisfaction,  have  lately 
made  some  experiments  to  clear  up  the  point. 
Commercial  iodine  was  taken,  mixed  with  a  fourth  of  its  weight 
of  potassium  iodide,  and  carefully  sublimed.  The  sublimate  was 
cooled,  powdered  and  placed  in  a  desiccator  to  remove  any  trace  of 
moisture.  This  chemically  pure  iodine  was  then  macerated  in 
chloroform  for  four  days,  the  temperature  remaining  nearly  constant 
at  iO°  C,  and  the  mixture  being  frequently  shaken. 
Iodine  being  very  volatile,  the  only  methods  of  estimation  possi- 
ble were  either  gravimetric,  as  argentic  iodide,  or  volumetric.  The 
latter  method  was  chosen  on  account  of  the  comparative  ease  and 
rapidity  of  the  process,  and  if  care  be  taken  to  "have  the  thiosul- 
phate  of  sodium  solution  correct,  it  is  quite  as  accurate  as  a  gravi- 
metric estimation.  The  result  of  a  large  number  of  estimations 
carefully  made  is  to  show  that  at  io°  C,  chloroform  dissolves  only 
