RESEARCHES  ON  BLACK  PHOSPHORUS. 
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cite,  and  their  sedimentary  formation,  having  been  thoroughly 
established,  I  examined,  starting  from  this  point,  graphite  (hith- 
erto regarded  as  being  without  structure,  but  doubtless  having  a 
Neptunian  origin)  and  the  diamond ;  and  by  the  experience  I 
have  gained  from  observing,  for  a  number  of  years,  chalcedony 
and  amber,  I  am  able  to  distinguish  sufficiently  between  me- 
chanical formations  and  formations  of  a  vegetable  origin.  I  have 
not  yet  attained  any  results  with  respect  to  graphite,  but  in  dia- 
monds I  have  found  numerous  foreign  bodies  enclosed,  of  which, 
if  they  cannot  be  said  to  be  evidently  and  undoubtedly  vegetable 
in  their  origin,  it  would  on  the  other  hand  be  difficult  to  deny 
their  vegetable  nature  altogether.  The  careful  figures  which 
will  accompany  my  essay  will  enable  others  to  judge  on  this 
point,  and  will,  if  nothing  else,  open  up  the  way  for  further  re- 
searches.— London  Pharm.  Journ.,  July  1,  1865,  from  Journal 
of  Botany. 
RESEARCHES  ON  BLACK  PHOSPHORUS. 
By  Dr.  Blondlot. 
The  color  of  crystallisable  phosphorus  presents  three  varieties 
— it  may  be  white,  yellow,  or  black.  The  last  variety  discovered 
by  Thenard  can  only  be  reproduced  accidentally,  and  indeed  its 
existence  has  been  doubted  by  most  chemists. 
Endeavoring  to  find  out  the  secret  of  this  preparation,  I  found; 
that  agreeably  to  Thenard' s  opinion  the  color  of  phosphorus  owes 
its  degree  to  the  way  in  which  it  is  cooled  after  having  been, 
melted. 
Phosphorus  is,  as  we  know,  purified  by  distillation.  I  perform 
this  operation  in  a  current  of  hydrogen  by  means  of  a  small 
tubular  retort,  heated  in  a  sand  bath,  and  adapted  to  a  flask  half/ 
full  of  water,  resting  at  the  bottom  of  a  large  vessel  filled  with 
water  at  70°.  On  dismounting  the  apparatus  there  is  usually 
found  a  certain  quantity  of  red  phosphorus  at  the  bottom  of  the 
retort.  Now  from  what  I  have  observed  it  is  in  the  production, 
and  in  the  successive  elimination  of  the  latter  that  the  conversion, 
of  ordinary  yellow  into  white  and  reputed  pure  phosphorus  con- 
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