242  A  VOYAGE  IN   SPACE

handed  over  the  finished  plate  and  put  in  the  new
one,  all  without  a  hitch  or  mistake  of  any  kind.  As
a  mere  piece  of  drill  the  performance  was  warmly
praised  by  a  military  man  present  in  the  audience.
During  the  long  (forty-second)  exposure,  the  party
of  observers  duly  took  the  opportunity  of  regarding
the  corona,  according  to  instructions;  but  for  the
rest  of  the  time  their  "  eyes  were  in  the  boat."  At
the  hundredth  second  the  corona  disappeared  with
the  reappearing  crescent  of  the  Sun,  and  the  lamps
previously  lowered  were  relit ;  the  eclipse  was  over ;
but  all  the  photographs  had  been  secured,  with
several  seconds  to  spare,  an  achievement  which  was
duly  appreciated  by  the  audience.]

Now  the  eclipse  is  over,  and  if  our  photographs
are  not  properly  taken  we  must  wait  till  the  next
eclipse;  we  cannot  repeat  this  one.  Fortunately
we  have  had  fine  weather — sometimes  poor  astron-
omers travel  thousands  of  miles,  get  everything
ready,  and  then  it  is  cloudy  or  raining  ! — but  I  feel
sure  that  when  we  develop  our  plates  we  shall  find
good  pictures  on  them.  And  now  what  is  the  use
of  these  pictures  when  we  have  them?  Well,  I
cannot  bother  you  with  all  the  details  of  eclipse
work,  but  I  will  try  to  give  one  or  two  illustrations
of  the  way  in  which  knowledge  may  be  gained  by
the  study  of  these  pictures;  and  I  will  take  the
illustrations  from  my  own  work  at  eclipses,  not
because  it  is  more  important  than  that  of  other
people,  but  because  I  know  more  about  it.
