524     SIMPLE  METHOD  FOR  PURIFYING  METALLIC  ARSENIC. 
composition  has  set  in,  the  heat  evolved  is  considerable,  but  even 
when  perfectly  young  and  fresh  all  the  Boleti  give  out  heat. 
Whilst  packing  up  the  three  large  and  beautiful  specimens  of 
B.  colopus,  Fr.,  exhibited  by  me  at  the  last  meeting  of  the  Royal 
Horticultural  Society,  I  noticed  the  decided  heat  evolved  from 
the  specimens.  At  the  time  of  packing,  my  plants  were  per- 
fectly fresh  and  young,  and  after  being  placed  in  a  light  paper 
box  for  a  short  time,  the  heat  evolved  was  apparent  to  the  hand. 
I  tested  the  heat  with  a  thermometer,  which  stood  outside  the 
box  in  a  shaded  room  at  70°,  this  after  being  placed  in  the  box 
with  the  Boleti  for  half  an  hour  rose  to  75°.  This  fine  species, 
though  I  believe  rather  rare  elsewhere,  is  common  in  early  au- 
tumn in  Epping  Forest,  where  it  grows  in  company  with  another 
beautiful  species,  B.  pachypus,  Fr.  Both  attain  here  very  large 
dimensions,  and  the  former  is  extremely  beautiful ;  the  tubes 
are  at  first  brilliant  yellow,  then  orange ;  the  stem  deep  carmine 
with  a  rich  maroon  base  ;  flesh  immediately  changing  to  bright 
blue  when  cut  or  broken. — Land.  Pharm.  Journ.,  Sept.  3,  1870, 
from  W.  Gr.  Smith  in  Gardners'  Chronicle, 
SIMPLE  METHOD  FOR  PURIFYING  METALLIC  ARSENIC. 
In  order  to  restore  to  this  metal  its  bright  aspect,  and  also  for 
the  removal  of  any  slight  coat  of  suboxide  which  may  adhere  to 
it,  the  author  advises  that  the  metallic  arsenic  should  be  boiled 
for  a  few  minutes  in  a  moderately  strong  solution  of  bichromate 
of  potassa,  slightly  acidified  with  sulphuric  acid.  The  metal  is 
next  first  washed  with  water,  and  then  with  alcohol  or  ether, 
and  lastly  placed  in  a  small  tube  closed  at  one  end,  and  sealed 
immediately  after  the  arsenic  has  been  put  into  it.  Phosphorus, 
which  has  been  kept  a  long  time  under  water,  and  has  become 
thereby  coated  with  a  whitish  yellow  crust,  may  be  treated  in 
the  same  way,  when  it  becomes  quite  colorless  again.  The  phos- 
phorus should  be,  of  course,  carefully  treated,  so  as  to  prevent 
its  ignition  ;  and,  after  having  been  well  washed  with  cold  water, 
should  be  preserved  in  water  freed  from  air  by  having  been  pre- 
viously boiled  for  a  long  time  and  cooled  in  a  well-closed  vessel. 
Lond.  Chem.  News,  Sept.  30,  1870. 
