PROCESS  FOR  PREPARING  JAMES'  POWDER. 
531 
position  nor  the  medical  effects  of  the  powder  of  James.  In  the 
manipulation  of  the  manufacturers,  the  chief  object  seemed  to 
be  the  production  of  a  powder  as  white  as  snow, — the  very 
quality  which  it  ought  not  to  possess  if  intended  to  resemble  the 
powder  of  James,  which  at  that  time  was  always  slightly  yellow, 
or  cream-colored,  or  even  stone-colored,  as  we  learn  from  Pear- 
son. 
I  made  a  number  of  trials  of  the  process  of  the  three  British 
Pharmacopoeias  (1816),  but  could  not  obtain  the  powder  white 
like  the  Pulvis  Antimonialis  of  the  druggists,  or  like  the  James's 
powder  then  in  use.  The  roasted  materials  introduced  into  a 
skittle-pot,  with  another  inverted,  both  luted  together,  were 
maintained  at  a  white  heat  in  an  air-furnace  for  two  hours. 
When  cold,  the  included  matter  was  found  converted  into  a 
dense,  close-grained,  buff-colored  mass,  as  hard  as  limestone  and 
very  heavy.  Being  again  heated  to  whiteness,  it  became  a  deep 
olive-brown  mass,  harder  than  before. 
I  repeated  the  process  on  new  materials,  heating  them  simi- 
larly in  a  different  air-furnace,  and  obtained  an  olive-brown  semi- 
vitrified  mass  with  dark  streaks,  harder  than  the  former  mass,  a 
small  portion  of  a  white  enamel  appearing  on  the  side  of  the 
skittle-pot. 
It  was  plain,  therefore,  that  the  heat  was  too  high,  and  that 
the  use  of  the  air-furnace,  originally  directed  by  Pearson,  and 
adopted  in  all  the  pharmacopoeias,  was  an  error.  I  therefore 
repeated  the  process,  and  placed  the  skittle-pot  containing  the 
powder  in  a  common  fire-grate,  heaping  coal  round  and  over  it. 
In  due  time  the  skittle-pot  became  red-hot,  and  in  this  state  it 
was  kept  for  an  hour  and  a  half  or  two  hours.  When  cold,Jt 
was  found  to  be  a  snow-white  powder,  covered  by  a  congeries  of 
crystals  a  quarter  of  an  inch  thick.  Thus  one  important  fact 
was  ascertained. 
On  repeating  this  method  several  times,  and  using  an  iron 
ladle  in  a  common  coal  fire,  the  resulting  powder,  instead  of 
being  uniformly  white,  proved  in  some  instances  to  be  buff- 
colored  ;  but  occasionally  the  snow-white  powder  was  obtained. 
As  the  failure  was  not  due  to  the  final  heating,  it  must  have 
originated  while  the  materials  were  in  the  iron  ladle.  Various 
