840 
ON  ANTIMONIAL  VERMILION. 
The  precipitate  which  is  produced  by  the  water  is  rapidly  dis- 
solved by  the  hyposulphite  of  soda  in  the  cold.  The  basin  is 
now  placed  in  a  water-bath  which  is  heated  to  boiling ;  in  this 
the  temperature  of  the  mixture  gradually  rises.  Towards  86°  F. 
the  precipitate  begins  to  form  ;  it  is  at  first  orange-yellow,  but 
gradually  becomes  darker.  The  temperature  is  allowed  to  rise 
to  131°F.,  when  the  basin  is  removed  from  the  water-bath,  and 
the  precipitate  is  allowed  to  settle,  which  takes  place  rapidly. 
The  fluid  is  separated  from  the  precipitate  by  decantation ;  the 
precipitate  is  washed  first  with  water  containing  one-fifteenth  of 
muriatic  acid,  and  afterwards  with  common  water,  then  collected 
on  a  filter  and  dried.  In  the  moist  state  the  antimonial  vermil- 
ion has  a  shining  red  color,  but  in  drying  it  loses  a  little  of  its 
lustre.  It  was  also  produced  in  the  cold,  but  the  process  de- 
scribed is  more  certain  and  furnishes  a  finer  color. 
The  author  has  analyzed  the  antimonial  vermilion  thus  pre- 
pared, and  at  the  same  time  examined  the  amount  of  water  in  the 
ordinary  orange-red  sulphuret  of  antimony  (precipitated  by  sul- 
phuretted hydrogen).  0-668  grm.  of  the  latter  lost  0-038  grm. 
in  weight  when  heated  to  392°  F. ;  0-808  grm.  of  antimonial 
vermilion  showed  a  loss  of  0-0098  grm.  when  heated  to  the  same 
temperature.  The  latter  might  be  attributed  entirely  to  hygros- 
copic water,  and  the  antimonial  vermilion  may  therefore  contain 
no  chemically-combined  water.  The  loss  of  weight  which  the 
orange-red  sulphuret  of  antimony  undergoes  shows,  on  the  con- 
trary, that  this  contains  water  chemically  combined,  and  this  loss 
of  weight  gives  it  the  composition  SbS3-f-HO.  The  further 
analysis  of  the  antimonial  vermilion  was  effected  by  treating  a 
weighed  quantity  of  it  with  nitromuriatic  acid  containing  an  ex- 
cess of  nitric  acid.  A  portion  of  sulphur  remained  undissolved, 
which,  after  tartaric  acid  had  been  mixed  with  the  fluid,  and  the 
latter  had  been  diluted  with  water,  was  separated,  dried,  and 
weighed.  The  fluid  contained  the  remainder  of  the  sulphur  in  the 
form  of  sulphuric  acid,  which  was  determined  by  precipitation 
with  chloride  of  barium.  The  antimony  was  merely  determined 
from  the  loss.  The  result  of  the  analysis  was,  that  the  anti- 
monial vermilion  consists  of  1-1  per  cent,  of  water,  26-7  per  cent, 
of  sulphur,  and  72. 2  per  cent,  of  antimony.    As  the  water  is  to 
