482     M.  F.  Zollner  on  the  Origin  of  the  Earth3 s  Magnetism, 
tible  by  the  quit's  rotation  in  the  thermometric  observations  if 
they  are  combined  for  a  sufficiently  long  period,  so  that  the 
yearly  and  daily  periods  may  be  considered  to  be  eliminated  from 
the  means.  In  the  third  volume  of  the  Bulletins  of  the  Ph.- 
math.  Class  of  the  Academy  of  Petersburg,  Nervander  has  shown 
that  the  coefficient  depending  upon  the  rotation  of  the  sun,  as 
determined  by  the  observations  in  Paris  from  1816-1839, 
amounts  to  0o,302  C.  The  difference  in  temperature,  therefore, 
observed  when  the  coldest  and  hottest  meridians  are  opposed  to 
the  earth  amounts  to  0o,604  C.  In  the  same  paper  this  quan- 
tity is  determined  by  the  observations  made  in  Innsbruck 
from  1777  to  1828;  the  number  arrived  at  agrees  perfectly 
with  the  results  of  Paris,  and  is  0°'60  C.  The  objection  has 
been  made  that  observations  of  two  places  only  cannot  prove  the 
existence  of  inequalities  directly  depending  on  the  rotation  of  the 
sun ;  but  the  probability  of  it  would  be  considerably  increased 
if,  under  very  different  climatic  conditions,  a  periodicity  of 
nearly  the  same  magnitude  should  be  deduced. 
"  In  this  respect,  since  1845,  only  the  Milanese  observations 
at  noon  have  been  reduced  by  Carlini.  With  other  observations, 
published  in  the  mean  time  in  PoggendorfFs  Annalen,  such  com- 
parisons cannot  be  made  as  are  required  to  decide  first  the  real 
existence  of  the  cause,  before  any  consequence  can  be  deduced 
from  it.  Carlini  found  the  inequality  arising  from  the  rota- 
tion of  the  sun,  according  to  the  Milanese  observations,  to  be 
0o,712  C.  The  close  agreement  of  this  number  with  that  found 
in  Paris  and  Innsbruck  is  the  more  surprising,  as  the  influence 
arising  from  inequalities  in  the  sun's  heating-power  must  make 
themselves  a  little  less  perceptible  in  higher  geographical  lati- 
tudes. The  discussion  of  the  Milanese  observations  comprises 
the  years  1835  to  1844. 
"  In  a  similar  manner  I  shall  in  this  paper  determine  the  co- 
efficient arising  from  a  possible  influence  of  the  sun's  rotation 
from  the  observations  made  at  the  Observatory  in  Konigsberg 
at  noon  from  1827-1837.  Beginning  with  the  meridian  M 
(turned  towards  the  earth  on  the  1st  of  January  1827  at  noon, 
Konigsberg  time),  I  have  put  together  in  the  following  Tables 
in  the  first  group  the  days  and  temperatures  which  belong  to  the 
same  meridian  M.  The  second  group  gives  the  days  and  tem- 
peratures belonging  to  the  heliographic  longitude  M  +  120°,  the 
third  those  of  long.  M  +  240°.  The  time  of  rotation  of  the  sun 
is  assumed  to  be  27*26  days"*. 
*  This  period  corresponding  very  nearly  to  the  more  reliable  recent  ob- 
servations, was  adopted  by  myself  as  well  as  by  Nervander  and  Carlini,  in 
order  to  make  the  results  of  the  Konigsberg  observations  more  comparable 
with  the  results  for  Paris,  Innsbruck,  and  Milan. 
