PROCESS  FOR  PREPARING  JAMES'  POWDER. 
583 
pot,  was  heated  in  a  well-built  and  well-supplied  fire  for  several 
hours.  The  powder,  when  cold,  was  found  to  be  yelio\^  through- 
out ;  for  the  proper  proportion  between  the  quantity  of  matter 
and  the  containing  iron  ladle  had  not  been  observed,  the  neces- 
sity of  which  was  thus  amply  proved.  It  is  a  certain  fact  that 
a  large  quantity  in  a  small  ladle  will  never  afford  a  white  pow- 
der. 
By  reversing  the  conditions  of  the  process,  that  is,  by  acting 
w^ith  due  care  on  a  small  quantity  of  materials  in  a  very  large 
ladle,  we  are  pretty  sure  of  bringing  the  charge  safely  through 
its  first  stage  of  danger.  Thus  when  four  ounces  of  hartshorn- 
shavings  and  the  same  weight  of  sulphuret  of  antimony  were 
well  raked  in  a  ladle  of  the  capacity  of  a  gallon,  until  the 
requisite  color  was  attained,  and  then  heated  in  the  skittle-pot 
for  an  hour  or  more  in  the  usual  manner,  the  powder  almost 
always  turned  out  white,  generally  snow-white,  but  sometimes 
with  the  cream-colored  tinge  noticed  by  Pearson.  Under  the 
condition  of  small  charges  in  a  very  large  ladle,  the  snow-white 
color  was  sometimes  produced  by  a  very  hot  fire  in  fifteen 
minutes  after  the  skittle-pot  had  become  red-hot,  but  with  a  fire 
not  so  hot,  a  much  longer  time  was  necessary. 
After  following  up  these  experiments  for  some  time,  I  found 
that  much  trouble  and  anxious  watching  would  be  saved  by  rak- 
ing the  bone-shavings,  without  the  sulphuret  of  antimony,  until 
the  ammoniacal  fumes,  the  sulphur,  and  the  extremely  fetid 
gases  had  been  expelled  ;  and  making  proper  allowance  in  sub- 
sequently apportioning  the  antimony. 
Adopting  this  method,  six  ounces  of  calcined  hartshorn-sHav- 
ings  mixed  with  foxi^  ounces  of  sulphuret  of  antimony  were 
raked  over  a  graduated  fire,  in  my  largest  ladle,  until  the  pow- 
der had  assumed  the  usual  yellowish-grey  hue.  It  was  then 
transferred  to  a  small  skittle-pot,  which,  being  placed  on  a  stand 
in  a  large  fire-grate,  coals  were  built  round  and  over  it,  and  a 
cover  applied.  The  skittle-pot  was  kept  red-hot  for  six  hours. 
When  cold,  it  was  cautiously  examined.  No  part  of  the  par- 
tially cohering  powder  was  white ;  it  was  almost  all  dark  grey, 
but  much  darker  towards  the  top ;  the  portion  at  the  very  top 
was  full  of  particles  of  metallic  antimony,  and  even  small  masses 
