( 439  ) 
Sterrenkunde.  — De  Heer  J.  A.  C.  Oüdemans  doet  eene  mede- 
deeling  over:  „Onderlinge  bedekkingen  en  verduisteringen  der 
wachters  van  Jupiter  in  1908.” 
TWEEDE  AFDEELING.  — VERDUISTERINGEN. 
Medegedeeld  in  de  vergadering  van  27  October  1906. 
Om  van  de  bedekkingen  over  te  gaan  tot  de  verduisteringen  is 
slechts  één  stap. 
Er  is  tusschen  deze  beide  verschijnselen  dit  verschil,  dat  de  be- 
dekkingen, zooals  boven,  blz.  180,  is  medegedeeld,  meer  dan  eens 
zijn  waargenomen,  terwijl  wij  van  die  eener  verduistering  van  den 
eenen  wachter  door  den  anderen,  slechts  één,  en  dan  geen  volledig 
bericht  kennen  uit  een  bijzonderen  brief  van  den  heer  Stanley 
Williams  van  7 December  1906.  Hij  schreef  ons  namelijk  ,,With 
„regard  to  the  heliocentric  conjunctions  there  does  seem  to  be  one 
„observation  of  the  rare  phenomenon  of  the  eclipse  of  a satellite 
„in  the  shadow  of  another  one  on  record.  It  occurred  on  the  14’^^^ 
„August  1901  and  was  observed  by  Mr.  J.  Comas  at  Valls  in  Spain 
„and  by  the  writer  at  Hove.  Mr.  Comas’  observation  was  published 
„in  the  French  periodical  L’ Astronomie,  1891,  p.  397  (read  398)  1), 
,,The  following  is  an  account  of  my  observation.  No  particulars  of 
,,this  have  hitherto  been  published. 
,,  „1891  Aug.  14.  6V2  inch  reflector,  power  225.  Defmition  good, 
,,  ,,but  interruptions  from  cloud.  Satellite  I.  transitted  on  the  S.  Equa- 
„ ,,torial  belt,  (N.  component).  Inimediately  on  its  entering  the  disc 
„ „it  became  lost  to  view.  At  11'’49™  a minute  dark  spot  was  seen 
,,  „about  in  the  position  which  the  satellite  should  have  then  occupied. 
„ „The  shadows  of  satellites  I.  and  II.  were  confounded  together  at 
,,  „this  time,  there  seeming  to  be  one  very  large,  slightly  oval,  black 
„ „spot.  At  11^59™  the  two  shadows  were  seen  neatly  separated, 
„ ,,thus,  . The  preceeding  shadow  must  be  that  of  II.,  the  follo- 
„ „wing  and  niuch  smaller  one  that  of  I..  At  12^10™  satellite  I.  was 
„ ,,certainly  visible  as  a dark  spot,  much  smaller  than  the  shadow 
„ ,,of  either  satellite.  It  had  moved  with  respect  to  the  shoulder  of 
„ „the  Red  >Spot  Hollow,  so  that  there  could  be  no  doubt  of  its 
„ „identity.  It  is  on  the  north  band  of  the  north  (south)  equatorial 
„ ,,belt  2).  Satellite  I.  [This  should  evidently  be  II.]  shines  brightly 
„ „011  the  disc  near  the  liinb.  Detinition  good,  but  much  thin  cloud 
,,  ,, about.”  ” 
„The  foregoing  is  an  al  most  literal  transcript  from  my  observation 
