FORMATION  OF  THE  GREEN  MATTER  OF  LEAVES  59 
tity  of  about  200  pounds  is  kept  heated  about  three  or  four 
weeks.  After  this  process  the  vessel  is  opened,  and  the  phos- 
phorus, which  has  now  become  a  hard,  red,  brick-like  substance, 
is  covered  with  water,  and  extracted  by  means  of  iron  bars,  &c. 
This  process  of  conversion  requires  to  be  conducted  with  great 
circumspection,  otherwise  (from  overheating  of  the  phosphorus) 
fearful  explosions  may  ensue  ;  experience  has,  however,  shown 
that  they  may  be  almost  wholly  avoided. 
For  commercial  purposes  the  red  or  amorphous  phosphorus, 
as  it  is  termed,  is  required  to  be  in  a  state  of  fine  powder ;  the 
stony  fragments  are,  therefore,  broken  into  small  pieces  under 
water  in  a  mortar,  and  ground  under  water  between  pieces  of 
mill-stone  in  a  vessel  supplied  with  a  small  stream  of  water, 
which  carries  off  the  finer  particles  in  its  overiiow  stream  into  a 
large  tank,  where  they  gradually  subside,  or  into  a  filter  where 
they  are  collected.  A  process  is  then  resorted  to  for  the  sep- 
aration of  any  ordinary  phosphorus  which  the  powder  may 
contain  Chem.  News,  London,  July,  1861. 
(To  be  continued.) 
FORMATION  OF  THE  GREEN  MATTER  OF  LEAVES  UNDER  THE 
INFLUENCE  OF  THE  ELECTRIC  LIGHT. 
M.  Herve  Mangon  has  published  the  results  of  some  experi- 
ments made  by  him,  with  a  view  of  ascertaining  whether  the 
green  matter  of  leaves,  &c,  would  be  formed  when  a  plant  was 
submitted  solely  to  the  influence  of  the  electric  light.  It  is  well, 
known  that  a  plant  grown  in  darkness  is  devoid  of  green  color 
and  it  is  generally  considered  that  the  sun's  light  is  essential  to 
its  development.  From  M.  Mangon's  experiments  it  appears 
that  the  electric  light  is  equally  capable  of  inducing  its  for- 
mation. 
The  electricity  was  produced  by  an  electro-magnetic  machine 
worked  with  a  steam  engine.  The  light  was  obtained  from  a 
lamp  with  charcoal  points.  The  light  was  maintained  for  eleven 
hours  on  the  30th  July,  twelve  hours  on  the  31st  July  and  1st 
and  2d  of  August,  and  eleven  hours  and  a  half  on  the  3d  of 
August.  The  temperature  of  the  air  varied  from  22°  to  25°  C, 
and  the  earth  from  19°  to  21°  C.     In  the  morning  of  the  30th 
