396 
POWDER  OF  THE  TURBIT-NITROUS  MINERAL. 
different  reactions  there  are  phenomena  worthy  of  notice.  First, 
on  commencing  the  operation,  there  is  a  disengagement  of 
whitish  fumes  (vapors)  from  the  nitric  acid,  which  volatilize 
before  combining,  caused  by  the  elevation  of  temperature. 
Secondly,  the  evaporation,  when  the  humidity  present  is  little, 
and  a  mass  commences  to  form,  whitish  fumes  are  given  off 
which  are  instantly  converted  into  violet  red;  the  first  are  deut- 
oxide  of  nitrogen,  which,  coming  in  contact  with  the  atmospheric 
air,  are  transformed  into  hypo-nitric  acid,  by  absorbing  some 
oxygen,  and  become  reddish — these  are  the  second.  Lastly,  when 
about  finishing  the  operation,  the  white  fumes  reappear  anew, 
which  in  this  case  is  that  the  nitrate  formed  begins  to  be  decom- 
posed into  nitric  acid  and  oxide  of  mercury,  and  so  readily, 
that  if  the  process  were  carried  on  there  would  be  a  decompo- 
sition in  total. 
Composition. — Opinions  disagreeing  in  regard  to  the  chemical 
composition  of  this  medicament,  it  is  considered,  according  to 
Mr.  J.  Estevez's  analysis,  a  suh-deuto  nitrate  of  mercury,  (nitrate 
bibasic.)  In  the  same  light  it  was  considered  by  Guibourt, 
Soubeiran,  Lassaigne,  and  other  chemists.  But  in  the  midst  of 
all  these  opinions  appears  Dr.  Kane,  who,  in  a  brilliant 
memoir  presented  to  the  Royal  Academy  of  Sciences  at  Paris, 
contended  that  the  bibasic  nitrate  of  mercury  treated  by  warm 
or  cold  water,  is  decomposed  into  a  liquid  acid,  very  soluble, 
and  a  yellow  precipitate,  which,  in  his  conception,  is  turbit- 
nitrous — unalterable  by  cold  water ;  but  that  warm  water  changes 
it  into  a  reddish-brown  color.  From  this  it  is  deduced  that  the 
yellow  precipitate  is  a  bibasic  nitrate  of  mercury,  composed  of  an 
atom  of  nitric  acid,  three  of  oxide  of  mercury,  and  one  of  water, 
which  we  have  proved  by  repeated  analysis  and  oxidation  of  72 
grs.  of  the  powder,  yielding  53  grs.  oxide  of  mercury,  losing  in 
the  evaporation  19  grs.  ;  and  supposing  this  to  be  nitric  acid, 
clear  it  is  that  it  will  bring  out  the  composition  proposed  by  Mr. 
Kane,  for  no  doubt  the  same  relation  exists  between  19  and  53 
as  between  1  and  3,  with  but  a  small  fraction  difference. 
