Am,May?i893arm' }  Observations  on  Decomposing  Chloroform.  243 
laboratory  when  dealing  with  them  led  me  to  give  up  the  idea  of 
attempting  to  follow  up  the  subject  quantitatively,  but  I  am  able  to 
say,  from  the  results  of  work  done  in  this  direction,  that  the  quan- 
tity of  carbonyl  chloride  found  in  different  samples  of  decomposing 
chloroform,  although  appearing  to  be  very  large,  judging  by  the 
powerful  smell  and  the  large  volume  of  vapor  evolved,  is  in  fact 
very  small,  o  57  per  cent,  being  the  highest  amount  found,  and 
further  that  the  ratio  which  exists  between  it  and  chlorine  precipita- 
ble  by  silver  nitrate  in  the  early  stages,  changes  as  decomposition 
advances,  the  former  decreasing  and  the  latter  increasing. 
In  the  early  stages  we  find  1  COCl2  to  1-29  HC1. 
In  the  later  stages  we  find  1  COCl2  to  4  69  HC1. 
The  ratio  as  represented  by  the  equations  in  similar  stages  is  1  to 
I  +  1  to  3,  the  difference  being  no  doubt  due  to  loss  of  carbonyl 
chloride. 
The  straw-colored  liquid  found  in  the  advanced  stages  contains 
no  free  chlorine ;  it  consists  of  a  strong  aqueous  solution  of  hydro- 
chloric acid  in  which  very  faint  traces  of  carbonyl  chloride  are  found 
and  contains  35-45  per  cent,  of  HC1. 
The  presence  of  this  liquid  in  the  advanced  stages  presents  diffi- 
culties which  cannot  at  present  be  satisfactorily  explained ;  it  seems 
highly  probable,  however,  that  the  hydrochloric  acid  produced  is 
dissolved  in  some  of  the  water,  which  would  otherwise  have  been 
used  in  decomposing  carbonyl  chloride. 
The  results  of  an  incomplete  investigation  which  have  been  laid 
before  you  do  not,  in  every  respect,  establish  the  correctness  of  the 
equations  given,  but  they  may  safely  be  accepted  as  representing 
changes  which  have  been  observed  during  the  decomposition  of 
chloroform  in  the  presence  of  a  limited  supply  of  air,  and  justify 
the  rejection  of  Prof.  Ramsay's  baryta  water  test  and  the  substitu- 
tion of  the  zinc  iodide  and  starch  one  for  it. 
The  chloroform  employed  was  pure,  of  sp.  gr.  1-500,  and  had 
been  dehydrated  with  barium  oxide. 
In  the  course  of  these  experiments  some  points  were  brought  out 
which,  although  they  do  not  throw  further  light  on  the  actual 
changes  which  take  place  during  decomposition,  may  be  new  to 
some  and  of  interest  to  others. 
Chloroform,  such  as  I  have  described,  has  been  exposed  to  sun- 
light in  a  Torricellian  vacuum  for  5  months,  equal  to  153  hours 
