Such  an  investigation,  he  said,  would  be  feasible  only  by  the
united  action  of  the  great  nations  of  the  world.
By  the  plan  adopted,  the  following  schedule  of  work  was
agreed  upon  for  each  of  the  several  stations  :  Meteorological
observations  :  temperature  of  the  air,  temperature  of  the  sea,
barometric  pressure,  humidity,  direction  and  force  of  wind,
kind,  amount,  and  motion  of  the  clouds,  rainfall,  and  weather
and  optical  phenomena.  Magnetic  observations  :  absolute  de-
clination, absolute  inclination,  absolute  horizontal  intensity,
variations  of  declination  and  inclination,  and  variations  of  hor-
izontal intensity.  All  these  observations  were  considered  ob-
ligatory, and  were  to  be  made  at  each  station  hourly  each  day,
excepting  on  the  1st  and  15th  of  each  month,  when  the  read-
ings were  to  be  made  every  five  minutes.  The  following  obser-
vations were  considered  desirable,  and  doubtless  have  gener-
ally been  made  :  Variations  of  temperature,  with  height,  solar
radiation,  evaporation,  galvanic  earth  currents,  parallax  of  the
aurora,  spectroscopic  observations  on  the  aurora,  ocean  cur-
rents, tidal  observations,  structure  of  ice,  density  of  sea-water,
atmospheric  electricity,  and  the  force  of  gravity.  The  several
expeditions  were  started  in  season  to  arrive  at  their  respec-
tive stations  by  the  date  assigned  for  beginning,  September  i,
1882.  .  ..
