270  MERCURY — ITS  OXIDES  AND  ACETATES,  ETC. 
The  examination  of  this  specimen  detected  no  red  oxide  of 
mercury,  but  the  black  oxide  in  about  the  same  proportions  as 
in  the  3d. 
From  the  characters  of  the  oxides  of  mercury,  it  would  ap- 
pear that  mercuric  oxide  is  not  formed  from  the  direct  action  of 
the  air  on  mercury  or  mercurous  oxide,  but  results  from  the  de- 
composition of  the  mercurous  oxide  by  the  action  of  moisture 
and  light,  by  which  the  mercurous  oxide  is  reduced  in  part  to 
a  metallic  condition,  the  other  part  passing  into  mercuric 
oxide. 
The  general  freedom  of  the  blue  mass  from  black  oxide  of  mer- 
cury, and  the  dry  condition  of  the  powdered  mass,  would  seem 
to  be  unfavorable  for  the  production  of  red  oxide  of  mercury  in 
powdered  blue  mass. 
METHOD  OF  PREPARATION. 
Powdered  Blue  Mass. — Nearly  all  of  the  powdered  blue  mass 
met  with  in  the  market  is  made  by  drying  the  mass,  powdering, 
and  then  making  up  the  deficiency  in  weight  by  adding  some  in- 
ert powder — generally  liquorice  root.  As  thus  met  with,  its 
color  varies  according  to  the  degree  of  fineness  of  the  powder  ; 
some  of  the  samples  we  examined  were  of  a  dark  slate  color, 
while  others  resemble  in  color  the  mercury  with  chalk. 
Two  samples  Obtained  from  good  manufacturers  showed  under 
the  microscope  globules  of  mercury  somewhat  larger  than  in 
the  mass ;  the  globules  were  less  evenly  distributed  than  in  the 
mass. 
Mercury  is  readily  extinguished  by  trituration  with  powdered 
liquorice  root,  adding  from  time  to  time  sufficient  water  to  keep 
it  in  the  consistence  of  a  paste. 
The  globules  are  not  visible  under  a  lens  of  two  or  three  di- 
ameters, but  if  the  pasty  mass  be  rubbed  between  the  thumb  and 
finger  till  dry,  the  liquorice  powder  is  rubbed  out,  leaving  glo- 
bules of  mercury  adhering  to  the  fingers  ;  when  dry,  the  pow- 
der is  in  a  rough  coarse  state  ;  an  attempt  to  pulverise  it  revives 
the  mercury.  If,  instead  of  water,  alcohol  is  used,  the  powder 
does  not  dry  so  hard;  but,  if  rubbed  under  the  pestle,  globules 
of  some  size  soon  appear.     Addition  of  honey  to  the  alcohol  in 
