and  the  Magnetic  Relations  of  the  Heavenly  Bodies.       459 
turbance,  which,  as  far  as  he  could  judge,  had  taken  place  simul- 
taneously with  the  phenomenon  observed  in  the  sun's  photo- 
sphere. This,  I  think,  is  the  first  example  of  a  connexion 
between  the  physical  changes  in  the  photosphere  and  the  mag- 
netic storms  or  disturbances  indicated  by  me  in  the  year  1852." 
Since  the  application  of  the  spectroscope  with  a  wide  slit  to 
the  observation  of  the  solar  surface,  and  chiefly  of  the  edges  of 
the  sun's  disk,  we  are  able  to  convince  ourselves  directly  of  the 
immense  power  of  the  eruptions ;  so  that  at  the  sight  of  these 
phenomena  the  probability  of  a  strong  reaction  on  the  liquid 
surface  and  its  currents  is  increased  almost  to  conviction. 
Through  a  friendly  communication  from  Professor  C.  A.Young, 
Dartmouth  College,  America,  who  is  in  possession  of  excellent 
spectroscopic  instruments  which  he  himself  has  much  improved 
by  ingenious  arrangements,  I  am  in  a  position  to  illustrate  here 
such  an  eruption  by  drawings  and  numerical  measurements. 
The  eruption  referred  to  belongs  probably  to  the  most  intense 
and  powerful  which  have  been  registered  during  the  short  time 
of  spectroscopic  observations  of  the  sun.  The  short  description 
of  the  phenomenon  with  the  drawings  of  the  observer,  as  com- 
municated by  Professor  Young  to  the  e  Boston  Journal  of  Che- 
mistry/ were  sent  to  me  while  this  paper  was  being  printed. 
[As  the  description  is  given  in  the  January  Number  of  the 
Phil.  Mag.,  it  is  not  necessary  to  reproduce  it  here.  Vide  supra, 
pp.  76-79.] 
It  is  to  be  seen  from  this  description  how  great  reactions 
take  place  on  the  solar  surface,  and  how  probable,  according 
to  my  theory,  the  supposition  is  that  such  sudden  appearances 
must  generate  magnetical  changes  in  the  sun  which  must  re- 
flect themselves,  if  sufficiently  intense,  in  the  magnetic  condition 
of  the  earth*. 
If  I  am  allowed  to  compare  the  character  of  the  phenomena 
just  described  with  terrestrial  appearances,  I  may  remind  the 
reader  of  air-  and  water-spouts,  where  for  a  long  time  quiet- 
ness and  stability  seem  to  reign,  which  suddenly  collapse,  be- 
traying by  mighty  movements  the  former  condition  of  whirl- 
like movements  in  the  inner  masses.  Indeed  the  five  stems  in 
fig.  1  recalled  to  my  mind  such  phenomena. 
18. 
These  facts  will  be  sufficient  for  the  present  to  show  at  least 
the  probability  of  the  existence  of  a  connexion  between  the  mag- 
netic condition  of  the  earth  and  sudden  changes  on  the  solar  sur- 
*  During  the  printing  I  receive  the  news,  as  an  answer  to  an  inquiry 
directed  to  the  Astronomer  Royal  (Mr.  Airy),  that  about  three  hours  after 
that  explosion  a  magnetic  storm  began  to  rage  on  the  earth. 
