426 
ON  A  NEW  METALLIC  ELEMENT. 
Kimeto,  or  niobic  acid  from  Bodenmais,  are  treated  in  the  same 
way,  the  solution  becomes  bluish  ;  and  on  adding  water,  the 
color  quickly  vanishes,  and  the  solution,  on  filtering,  passes 
through  colorless. 
When  dianic  acid  is  boiled  with  chlorhydric  acid  and  zinc, 
instead  of  with  tin,  the  blue  solution  does  not  appear,  the  pre- 
cipitated acid  becomes  blue,  but  filters  colorless,  and  is  decolor- 
ized by  water  without  being  sensibly  dissolved.  When  equal 
quantities  of  dianic,  tantalic,  and  hyponiobic  acids  are  boiled 
with  concentrated  chlorhydric  acid,  upon  a  funnel  of  platinum- 
foil  for  three  minutes,  all  three  give  yellowish  milky  liquids;  if 
water  be  then  added,  the  solution  of  dianic  acid  becomes  perfectly 
clear,  while  the  tantalic  and  hyponiobic  acids  remain  undissolved. 
When  freshly  precipitated  dianic  acid  is  heated  to  boiling  with 
dilute  sulphuric  acid,  the  milky  liquid  poured  into  a  glass,  and 
grains  of  distilled  zinc  thrown  in,  the  dianic  acid  in  a  few  mo- 
ments becomes  smalt  blue,  even  dark  blue,  and  retains  this  color 
for  some  time  on  addition  of  water  ;  but  the  liquid  passes  through 
the  filter  colorless.  In  this  respect,  dianic  acid  resembles 
hyponiobic  acid,  while  tantalic  acid,  under  the  same  circum- 
stances becomes  pale  blue,  and  immediately  loses  this  color  on 
addition  of  water.  In  this  manner,  tantalic  may  be  distinguish- 
ed from  dianic  and  hyponiobic  acids.  The  relations  of  the  three 
acids  to  chlorhydric  acid  and  tin,  and  to  sulphuric  acid  and 
zinc,  are  thus  sufficient  to  distinguish  them  from  each  other. 
Dianic  acid  appears  to  exist,  though  in  a  less  pure  state,  in 
the  tantalite  from  Greenland,  in  pyrochlore  from  the  Ilmenge- 
birg,  and  in  the  brown  Wohlerite — though  the  author  had  but 
small  quantities  of  these  minerals  at  his  disposal.  A  small 
piece  of  black  yttrotantalite,  believed  to  be  from  Ytterby, 
gave  the  reaction  of  dianic  acid.  A  second  specimen,  however, 
the  specific  gravity  of  which  was  found  to  be  5-55,  contained 
tantalic  acid. 
Titanic  acid  is  easily  distinguished  from  the  other  acids  of  the 
same  group,  by  boiling  it  with  muriatic  acid  and  tin,  and  dilu- 
ting the  solution  with  water.  The  blue  color  then  passes  to 
rose  red,  and  the  solution  retains  this  color  several  days.  When 
dianic  acid  is  present,  the  blue  color  predominates,  but  after 
standing  some  hours  the  rose  color  of  titanic  acid  appears. 
