and  the  Magnetic  Relations  of  the  Heavenly  Bodies.        361 
locity  peculiar  to  the  liquid — similar  to  the  circular  waves  going 
out  on  a  quiet  surface  of  water  from  a  point  where  a  stone  has 
fallen  into  the  water. 
It  is  evident  that  the  velocity  of  propagation,  as  well  as  the 
form  of  the  waves,  will  be  essentially  moditied  if  the  liquid  is  not 
quiet,  but  flowing  with  a  uniform  velocity. 
In  a  direction  perpendicular  to  the  current  the  waves  will  pro- 
pagate themselves  with  the  velocity  peculiar  to  the  liquid ;  par- 
allel to  the  current  they  will  propagate  themselves  more  quickly 
in  the  direction  of  the  current  than  in  the  opposite  direction.  At 
the  same  time  the  form  of  the  waves  will  be  more  extended  and 
drawn  out  on  the  side  of  the  centre  of  the  waves  situated  in  the 
direction  of  motion.  The  height  of  the  waves  will  depend  upon 
the  borders  of  the  liquid ;  it  will  increase  where  the  liquid  is 
hemmed  in. 
Let  us  now  apply  these  simple  laws  of  hydrodynamics,  mutatis 
mutandis,  to  the  glowing  liquid  in  the  nucleus  of  our  earth. 
Other  modifications  of  the  wave,  generated  in  the  above  manner, 
will  appear  in  the  direction  of  the  circles  of  latitude  than  in  the 
meridian.  In  the  first  direction  the  wave  will  proceed  as  in  a 
circular  channel  on  both  side^  of  the  disturbed  spot,  and  cause 
at  a  point  about  180  degrees  distant  from  it  the  opposite  phase 
of  that  by  which  the  wave  was  originated.  In  the  present  case 
this  would  be  a  wave-mountain.  But  as  a  rising  of  the  liquid  ne- 
cessarily increases  the  pressure  against  the  solid  crust,  and  must 
hence  also  increase  the  friction  of  the  glowing  mass  flowing  east- 
ward, it  is  clear  that  an  oscillation  of  the  magnetic  constants 
will  take  place  parallel  to  the  direction  of  propagation. 
It  is  clear  moreover  that  the  direction  of  propagation  of  a 
liquid  wave  must  be  distinguished  from  the  direction  of  the  cur- 
rent as  regards  the  electromotive  action  produced  by  it.  The 
mechanical  process  on  which,  according  to  my  views,  the  origin 
of  the  electrical  current  depends,  consists  in  a  relative  dis- 
placement of  parallel  liquid  threads  taking  place  always  in  the 
same  direction.  By  the  researches  of  the  brothers  Weber  it  was 
directly  proved  that,  in  an  undulatory  motion  of  liquid  bodies, 
the  particles  are  moving  in  more  or  less  closed  paths  of  compa- 
ratively small  radii  of  curvature.  A  wave-mountain  of  the 
glowing  liquid,  produced  a3  described,  cannot  but  cause  an  in- 
crease of  the  hydrostatic  pressure  in  whatever  direction  it  pro- 
pagates itself.  Hence  all  the  actions  caused  by  a  change  in  the 
velocity  of  motion  of  the  glowing  liquids  (as,  for  instance,  the 
magnetic  action)  can  only  be  increased  by  such  a  wave,  as  the 
hydrostatic  pressure  becomes  greater,  with  which,  according  to 
the  experiments  of  Quincke,  cited  above,  the  intensity  of  the 
diaphragmic  currents  varies  directly. 
