METALS.
741
The  oxide  thus  obtained,  is  to  be  put  into  a  crucible,  and
melted  in  a  brisk  fire,  without  any  addition  ;  it  generally
forms  a  brown  transparent  glass.  If  the  antimony  has  been
calcined  too  much,  it  is  rather  hard  to  melt  ;  some  chemists
in  this  case,  throw  a  little  common  antimony  into  the  crucible ¬
  ;  but  this  addition  gives  the  glass  a  darker  colour  than
if  pure.
It  is  used  to  prepare  tartar  emetic.
Some  years  ago  a  druggist,  being  distressed  and  in  the  King’s  Bench
Prison,  made  a  quantity  of  glass  of  lead,  coloured  it  to  imitate  glass  of
antimony,  and  sold  it  for  that  article  before  the  fraud  was  discovered.
Some  of  this  glass  still  remains  in  the  apothecaries'  shops,  to  whom  it
was  sold.
Glass  of  antimony  varies  in  its  ingredients,  according  to  the  quantity
of  silica  that  it  extracts  from  the  crucible.
Crocus  Metallorum.
This  is  made  by  calcining  common  antimony  until  it  acquires  only  a
dull  grey  colour,  and  then  melting  it  in  a  crucible.
It  is  used  to  make  emetic  tartar.
Emetic  Tartar.
The  old  process  for  making  this  double  salt,  was  to  mix
one  pound  of  crocus  metallorum  with  a  pound  of  cream  of
tartar,  boil  the  mixed  powder  in  a  gallon  of  water  for  an
hour  or  two,  filter,  evaporate  to  a  pellicle,  and  set  it  by  to
crystallize;  the  mother  water  is  again  evaporated,  until  it
ceases  to  yield  crystals.
But  since  glass  of  antimony  has  been  manufactured  on  a
large  scale,  and  thus  may  be  bought  cheaper  than  the  crocus -
  can  be  made,  it  has  been  used  in  preference.
A  number  of  other  processes,  some  of  them  very  complicated, ¬
  have  been  given  for  making  this  salt;  but  their  use
have  been  confined  to  their  inventors,  as  all  the  wholesale
makers  of  emetic  tartar  use  one  or  other  of  the  above
methods.
Emetic  tartar  is  at  present  the  most  generally  used  antimonial  medicine, ¬
  and  its  exhibition  may  be  managed  so  as  to  produce  either  sweating, ¬
  purging,  or  vomiting,
Berzelius  calls  this  salt  tartras  kalico  stibicus,  ôr  3  K:  T  -2Aq2+
—»  Aq’,  and  thus  makes  its  atomic  weight  28,235,830.  Dr.  T.
4  Sb:1
Thomson  thinks  it  should  be  called  ditartrate  of  potash  and  antimony,
considers  its  composition  to  be  T  —  Sb;  +  T—  K:  Sb;  +  2  Aq,  and
its  weight,  44,250.  Gay-Lussac  thinks  the  cream  of  tartar  performs  in
this  and  similar  salts,  the  part  of  a  simple  acid.
Kermes  Mineral.
The  best  process  for  making  this  medical  article,  much
used  by  the  Continental  physicians,  is  to  boil  one  pound  of