448     M.  F.  Zollner  on  the  Origin  of  the  Earth's  Magnetism, 
to  great  distances,  but  also  that  the  forces  which  cause  the 
earthquake  modify  in  a  certain  degree  the  magnetism  of  the 
earth.  The  modification  consists  doubtless  in  the  production  of 
an  earth-current,  which  in  the  above  case  was  so  far  confirmed, 
as  the  instruments  at  the  observatory  in  this  town  indicating 
earth-currents  showed  at  that  time  unusual  activity." 
14. 
The  phenomena  which  we  have  discussed  embrace  in  general 
all  those  facts  which,  independent  of  the  relations  of  the  earth 
to  other  heavenly  bodies,  express  merely  a  relation  of  terres- 
trial conditions  and  changes  to  terrestrial  magnetism.  In 
the  following  I  have  the  intention  to  discuss  as  well  those  phe- 
nomena which  prove  in  a  definite  manner  a  magnetical  relation 
between  the  earth  and  other  heavenly  bodies. 
As,  according  to  our  theory,  the  streaming  process  in  the 
glowing  liquid  nucleus  of  the  earth  is  only  a  repetition  of  the 
streaming  process  on  the  sunV  surface,  the  same  causes  must 
lead  to  the  same  consequences. 
The  sun  therefore  is,  for  these  reasons,  to  be  regarded  as  a 
magnetic  body  like  the  earth,  whose  poles  of  rotation  in  general  do 
not  coincide  with  the  magnetic  poles. 
But  assuming  the  same  relation  between  the  direction  of  the 
liquid  and  electrical  currents  in  the  liquid  solar  surface,  it  fol- 
lows that  the  poles  of  the  sun  have  the  opposite  magnetic  pola- 
rity to  the  corresponding  poles  of  the  earth ;  for  as  the  solar 
surface  does  not  yet  possess  a  solid  crust,  and  according  to  the 
law  of  rotation  the  currents  on  it  are  generated  by  friction 
against  the  polar  undercurrents  of  the  atmosphere,  these  north- 
easterly currents  have  the  opposite  direction  to  the  south-westerly 
equatorial  currents  in  the  inner  part  of  the  earth.  Considering, 
therefore,  the  rotation  of  the  sun  to  be  in  the  same  direction 
as  the  rotation  of  the  earth,  the  former  must  have  a  magnetic 
south  pole  where  the  latter  has  a  magnetic  north  pole. 
As  regards  the  layers  in  which  the  generated  electrical  ten- 
sions are  equalized  by  electrical  currents,  the  inferior  layers  of 
the  sun's  atmosphere,  which  are  dense  and  rich  in  vapour,  take 
the  place  of  the  under  parts  of  the  earth's  crust.  It  is  not  im- 
probable that  we  observe  this  restoration  of  the  electrical  equi- 
librium in  the  form  of  protuberances,  especially  the  protube- 
rances which,  as  it  were,  cover  with  a  bridge  deeper-lying  parts, 
and  through  the  darkness  of  the  covered  space  have  given  rise  to 
the  supposition  of  dark  protuberances*. 
*  The  observations  of  protuberances  made  by  Respighi,  Tacchini,  C.  A. 
Young,  Norton,  and  others  contain  numerous  indications  of  the  similarity 
of  the  images  of  certain  protuberances  to  the  aurora  borealis ;  and  the  inner 
