446     M.  F.  Zollner  on  the  Origin  of  the  Earth's  Magnetism, 
believe  they  already  make  manifest  that  the  introduction  of  this 
idea  was  dictated  by  the  nature  of  the*  subject. 
In  conclusion,  I  will  take  the  liberty  to  state  again  expressly 
the  points  to  which  Mr.  Tait  objects,  in  order  to  prevent  any 
subsequent  shifting  of  the  position.     Mr.  Tait  maintains  :-— 
(1)  That  the  theorem,  that  heat  cannot  by  itself  pass  from  a 
colder  into  a  hotter  body,  is  fallacious ;  and 
(2)  That  the  introduction  of  the  notions  of  internal  work  and 
of  disgregation  was  detrimental  to  science. 
The  decision  on  these  two  points,  so  far  as  they  are  at  all  still 
doubtful,  I  think  I  may  confidently  leave  to  the  future;  and 
thereby  this  controversy  also  will  finally  and  fully  decide  itself. 
Bonn,  May  1872. 
LVII.   On  the  Origin  of  the  Earth's  Magnetism,  and  the  Mag- 
netic  Relations  of  the  Heavenly  Bodies.     By  F.  Zollner. 
[Continued  from  p.  365.] 
13. 
IT  is  to  be  expected,  according  to  the  views  above  developed 
as  to  the  physical  causes  of  the  earth's  magnetism*,  that 
there  exists  a  connexion  between  all  the  phenomena  related  to 
this  magnetism  and  the  volcanic  appearances  on  the  surface 
of  the  earth..  In  fact,  if  these  processes  are  to  be  looked  at  ac- 
cording to  the  principles  of  every  rational  geology,  as  reactions 
of  the  glowing  liquid  nucleus  of  the  earth  on  its  solid  crust,  these 
reactions  must  manifest  themselves  as  well  by  mechanical  as  by 
electrical  and  magnetical  effects.  The  first  of  these  effects  are 
observed  in  the  earthquakes  and  volcanic  eruptions,  the  latter 
in  the  oscillations  of  the  magnetic  needle.  The  close  connexion 
of  these  two  kinds  of  appearances  which  is  necessarily  demanded 
by  our  theory  is  confirmed  by  numerous  observations.     I  will 
*  Whilst  this  paper  passes  through  the  press  I  receive  the  news  of  a 
very  remarkable  observation  which  was  made  a  short  time  ago  in  France 
at  the  boring  of  a  very  deep  artesian  well.  The  Academy  of  Paris  has  re- 
ceived on  this  subject  a  communication,  printed  in  the  Comptes  Rendus, 
vol.  lxxiii.  p.  910,  under  the  title  "Etude  de  l'eau  artesienne  de  Rochefort 
Note  de  M.  Roux  (extrait)."  The  passage  in  question  is  the  following : — 
"  Une  particularity  interessante,  que  nous  avons  observee  pendant  les  tra- 
vaux  artesiens  est  Taimantation  energique  de  la  sonde.  Ses  tigues  desar- 
ticulees  apres  le  travail,  constituaient  autant  d'aimants  partiels,  ayant  cha- 
cune  son  pole  boreal  et  son  pole  austral."  Considering  the  weak  magnetism 
of  the  minerals,  this  curious  observation  can,  I  think,  only  be  explained 
by  the  existence  of  strong  electrical  currents  in  the  earth,  which  would 
agree  with  the  laws  of  the  ramification  of  currents  relative  to  their  intensity. 
Note  by  the  Translator. — I  have  been  told  that  an  earthquake  at  Lisbon 
in  the  year  (1858?)  was  coincident  in  point  of  time  with  a  considerable 
disturbance  of  the  magnets  at  the  Kew  Observatory. 
