292 
ON  CHLOROFORM. 
form.  If  this  chloroform  was  exposed  for  a  short  time  to  the 
sunlight  in  filled  or  half-filled  bottles,  it  contained  hydrochloric 
acid  and  phosgene  gas  ;  but  it  kept  unaltered  if  excluded  from 
the  sunlight;  diffused  daylight  has  the  same  effect  after  a  longer 
period  ;  freed  by  sodium  from  all  adhering  moisture,  it  was  de- 
composed in  precisely  the  same  manner.  Pure  chloroform  is  not 
affected  by  diffused  daylight  or  direct  sunlight,  if  preserved  in  a 
perfect  vacuum. 
At  the  close  of  his  paper,  Dr.  C.  Schacht  gives,  from  Dingler's 
Polytech.  Journ.,  Oct.,  1867,  a  short  account  of  the  results  as 
published  in  my  previous  paper;  and  from  his  remarks  it  is  evi- 
dent that  he  has  not  tried  the  behaviour,  in  the  direct  sunlight, 
of  chloroform  reduced  by  alcohol  to  the  specific  gravity  of  1*475. 
The  points  which,  according  to  the  above  papers,  seem  to  re- 
quire investigation,  are — 
1.  The  process  and  material  employed  in  the  manufacture  of 
chloroform  prone  to  spontaneous  decomposition; 
2.  The  regeneration  of  chloroform  which  has  been  decomposed 
by  light ; 
3.  Additional  proof  that  chloroform  of  1*475  is  not  decomposed 
by  sunlight. 
Daring  the  year  1864,  and  in  the  early  part  of  1865,  very 
considerable  quantities  of  chloroform  were  made  at  the  U.  S. 
Army  Laboratory  of  this  city,  under  my  personal  supervision. 
Some  of  this  chloroform  was  found  to  be  rapidly  decomposed 
when  kept  on  the  shelves,  and  this  observation  led  to  the  experi- 
ments which  resulted  in  determining  the  fact  that  a  reduction  of 
its  specific  gravity  by  alcohol  prevents  this  decomposition. 
I  had  the  following  apparatus  built  for  preparing  and  rectify- 
ing chloroform  : 
The  still  was  made  of  heavy  boiler  iron,  8J-  feet  high  and  3 
feet  diameter,  with  a  capacity  of  about  780  gallons  ;  the  top  and 
bottom,  being  sections  of  a  sphere,  were  of  cast  iron.  The  whole 
rested  upon  four  feet  made  of  heavy  iron  pipe,  and  was  placed  a 
few  inches  below  the  level  of  the  floor,  so  that  the  discharge  cock 
could  be  conveniently  turned.  This  latter,  a  so-called  two-inch 
round  way  cock,  connected  by  means  of  a  bent  iron  pipe  with  the 
bottom  of  the  still,  the  contents  of  which  could  thereby  be  run 
