This  button  of  regnlus  must  be  very  finely  pulverized  in  a
mortiir,  witli  a  little  charcoal  or  coke,  care  being  taken  that
none  h  lost,  either  over,  or  by  sticking  to»  tlic  mortar;  then
transferred  to  another  similar  sized  crucible,  for  re-oxidation
by  eecoodary  roasting*

C.  RoASTiNU  THE  Regulus — ^Is  ctlbcted  by  placing  the
crucilde  on  the  fire,  warming  it  gradually  during  continual
stirring  with  a  steel  or  iron  rod,  for  about  twenty-tive  min-
utes, until  it  shows  an  earthy  appearance,  and  all  sulphurous
fumes  have  ceased,

D.  Smelting  of  the  Sulpuide  Eeoulus  for  Impure  Cop-
per.— Mix  (in  the  same  crucible)  with  this  ''roasted  regulus"
25  grains  of  nitre  (nitrate  of  potash,  or  saltpetre),  25  grains


*  In  fluxing  for  reguhis,  the  effects  Bought  are  a  fusible  pUjj  (produced  by
borax  and  Cluur  spar),  which  shall  iilso  conlaiti  the  copper,  etc.,  when  uxidii^ecl
amd  fused  to  giilphide  forois ;  hence,  the  nddition  uf  sulphur,  or  sulphurets
of  irotit  to  certain  ores,  Ihat  do  not  conUiin  sulphur  iu  iheir  natural  couf^Jilu-
tioDAl  forms.
The  liuie  facilitates  the  separation  of  th3  lighter  slrutura  of  the  sing  from  the
regotus.
MRTALLURaiSTS'   COMPANIOK.  801

of  borax,  15  grains  of  coal  powder,  100  grains  of  dry  salt,
and  200  grains  of  tartar.  Cover  this  mixture  with  a  table-
spoonful  of  common  salt.

### Language ###
English

### Assessment ###
Extract the specific duration mentioned for roasting the regulus in the process.

### Query ###
How long should regulus be roasted while stirring?
How long should regulus be roasted while stirring?