300 
ON  CHLOROFORM. 
was  pushed  far  enough  until  active  boiling  commenced,  and  it 
now  vacillated  between  66°  and  67°  C.  (151°  and  153°  F.) 
The  distillate  was  again  returned  to  the  retort,  and  heated  in 
a  water-bath,  the  whole  of  the  chloroform  being  immersed.  Care- 
fully heated,  the  temperature  in  the  retort  rose  to  69°  C.  (156° 
F.)  without  the  slightest  sign  of  boiling.  Some  fragments  of 
glass  were  dropped  in,  when  it  boiled  violently  for  a  few  seconds, 
the  mercury  at  the  same  time  receding,  after  which  the  boiling 
continued,  the  thermometer  varying  several  times  between  64° 
and  64-5°  C.  (147°  and  148°  F.)  After  boiling  ceased,  a  few 
drops  remained  in  the  retort,  which  immediately  imparted  a 
yellowish-brown  color  to  sulphuric  acid,  while  the  distillate  was 
without  reaction  even  after  prolonged  contact. 
This  chloroform  had  been  prepared  by  the  process  given  above, 
from  good  ordinary  alcohol  of  95  per  cent,  by  volume,  not  en- 
tirely deprived  of  fusel  oil. 
A  sample  of  chloroform  obtained  from  a  manufacturer  had 
the  specific  gravity  of  1*484,  was  fiee  from  reaction  on  litmus, 
and  scarcely  affected  sulphuric  acid.  It  behaved  to  the  direct 
and  diffused  sunlight  precisely  like  the  one  mentioned  before. 
This  chloroform  was  rectified  by  very  slow  distillation  over  chlo- 
ride of  calcium,  and  the  distillate  collected  in  fractions  of  three 
ounces  each.  Sulphuric  acid  was  avoided,  because  it  has  been 
supposed  by  some  to  induce  decomposition.  Some  chloroform 
prepared  by  myself  was  properly  reduced  by  the  addition  of 
alcohol,  and  then  rectified  in  the  same  manner  over  chloride  of 
calcium. 
The  fractions  varied  in  specific  gravity  from  1*478  to  1*494, 
and  all  were  uniformly  exposed  to  sunlight  for  one  day,  when 
some  of  the  heavier  (1*480  to  1*484)  were  found  to  be  acid,  while 
other  fractions  of  the  same  gravity  retained  their  neutral  be- 
haviour to  test  paper.  On  examining  the  bottles  a  slight  con- 
densation of  moisture  was  observed  above  the  acidified  chloroform, 
while  the  samples  retaining  their  neutral  reaction  were  free  from 
it.  This  latter  chloroform  was  now  emptied  into  damp  bottles 
and  exposed  to  the  sunlight  for  about  three  hours,  when  litmus 
was  instantly  colored  red,  and  in  the  course  of  a  few  seconds  en- 
tirely bleached.    Both  chloroforms  behaved  precisely  alike. 
