Occasionally  a  soft  lambent  glow  has  been  ob-
served on  snowfields  at  night.  This  is  a  very
curious  phenomenon,  to  which  the  name  of
"phosphorescence"  has,  rightly  or  wrongly,
been  given.  A  pale  light  may  often  be  seen  on
the  sea  during  a  summer  night,  when  the  water
is  disturbed  in  any  way  ;  and  if  one  is  rowing  in
a  boat,  the  oars  seem  glowing  with  a  faint  and
beautiful  light.  It  is  well  known  that  this  is
caused  by  myriads  of  little  light-producing  ani-
malcules in  the  sea-water.  But  we  can  hardly
suppose  that  the  glow  above  referred  to  is  pro-
duced by  a  similar  cause.  One  observer  says  the
glow  is  "something  like  that  produced  by  the
flame  of  naphtha  j"  and  he  goes  on  to  say  that  at


78  The  Story  of  the  Hills.
every  step  "  an  illuminated  circle  or  nimbus  about
two  inches  in  breadth  surrounded  our  feet,  and
we  seemed  to  be  ploughing  our  way  through
fields  of  light,  and  raising  clods  of  it,  if  I  may
be  allowed  the  expression,  in  our  progress."  An-
other observer,  also  an  Alpine  traveller,  says  that
at  almost  every  footstep  the  snowy  particles,
which  his  companion  in  front  lifted  with  his
feet  from  the  freshly  fallen  snow,  fell  in  little
luminous  showers.  The  exact  cause  which  pro-
duces this  strange  effect  at  night  has  not  been
ascertained.
There  is  another  curious  phenomenon  often
seen  just  before  sunset  on  a  mountain  in  Hungary.
