602  Contribution  to  the  Knowledge  of  Boron.  {Amv™*\m&Tm* 
aqueous  solutions  left  after  making  the  above  tests  were  allowed  to 
evaporate  spontaneously  over  sulphuric  acid  and  deposited  a  somewhat 
crystalline  residue,  most  marked  in  the  Georgia  sample  and  least  in  the 
refined  sample.  No  sediment  was  found  in  any  of  the  samples,  and 
they  dissolved  completely  without  leaving  sand,  chips,  or  clay 
behind. 
It  is  suggested  that  this  refined  tar  had  lost  much  of  the  pyrocate- 
chin  through  contact  with  water. 
It  appears  from  the  above  results  that  the  best  method  of  examin- 
ing a  sample  of  tar  would  be  to  take  its  specific  gravity,  try  its  solu- 
bility with  the  above  solvents,  and  examine  the  ethereal  solution  of  the 
aqueous  extract  for  pyrocatechin.  Comparing  a  thin  layer  on  glass 
with  a  sample  of  known  purity,  a  microscopic  examination  would  also 
be  of  value  in  determining  the  quality  of  a  sample. 
CONTRIBUTION  TO  THE   KNOWLEDGE  OF  BORON. 
By  Henry  C.  C.  Maisch,  Ph.G.,  Ph.D. 
During  his  researches  on  the  electrolysis  of  the  alkaline  oxides  and 
hydroxides,  Sir  H.  Davy  also  subjected  boric  acid  to  the  action  or 
the  electric  current  (Phil.  Trans.  Royal  Society,  1808,  p.  43).  He 
obtained  a  black  combustible  substance,  which,  however,  he  did  not 
further  describe.  Without  doubt  he  was  the  first  to  obtain  boron  in 
the  free  state,  though  to  two  French  chemists,  Gay  Lussac  and  Thenard 
(Gilb.  Ann.  der  Phys.,  1808,  p.  30),  belongs  the  credit  of  first  describ- 
ing the  element,  which  they  obtained  by  the  action  of  potassium  on 
melted  boric  acid.  During  the  year  1888,  W.  Hampe  (Chem.  Zeit., 
xii,  841)  prepared  boron  by  the  electrolysis  of  borax,  which  he  melted 
in  a  graphite  crucible. 
Wohler  and  Deville  (Ann.  Chim.  Phys.,  1858  (3),  lii,  p.  84)  during 
their  classic  researches  on  boron  and  its  compounds  employed  the 
process  of  Gay-Lussac  and  Thenard,  using  potassium  or  sodium,  but 
they  also  found  that  by  using  aluminium  crystalline  boron  was 
obtained. 
We  are  indebted  to  Berzelius  for  two  further  methods:  (1)  by  the 
action  of  potassium  on  boron  fluoride,  and  (2)  by  the  action  of  potas- 
sium borofluoride  at  the  fusing  point  of  the  former.  Wohler  and 
Deville  (I.  c.)  and  Geuther  (Jenaische  Zeitschr.  filr  Med.  und  Naturw., 
