the  Principle  of  the  Conservation  of  Energy.  129 
If  we  put  c  =  439450  .  106  millimetre  it  follows  from  this  last 
second 
determination  that  the  value  of  p  must  lie  approximately  between 
*    ■  and   — l— -  of  a  millimetre  in  order  that  these  oscillations 
4000  SO 0  0 
may  be  equal  in  rapidity  to  those  of  light. 
The  difference  of  the  electrical  particles  e,  e1  and  of  their 
masses  e,  e!  in  the  case  of  small  values  of  -9  and  small  ampli- 
tudes, does  not  affect  the  oscillations  at  all;  and  in  the  case  of 
greater  amplitudes  it  affects  them  only  so  far  as  the  value  of  p 
depends  upon  it. 
15.  Applicability  to  Chemical  Atomic  Gh'oups. 
The  distinction  between  two  or  more  states  of  aggregation  of 
bodies,  according  as  they  consist  of  simple  atoms,  or  of  atomic 
pairs,  or  of  groups  of  more  than  two  atoms,  has  acquired  great 
importance  in  relation  to  chemistry.  Now  one,  and  now  another 
state  of  aggregation  occurs ;  and  in  many  chemical  processes  a 
transition  takes  place  from  one  to  another;  but  the  intermediate 
states  which  occur  in  the  case  of  such  transition  cannot  exist 
permanently,  and  those  states  of  aggregation  are  consequently 
completely  separate  from  each  other  as  permanent  states. 
Now  it  is  obvious  that  the  permanence  of  some  atomic  condi- 
tions, which  are  distinguished  as  special  states  of  aggregation, 
and  the  want  of  permanence  in  all  other  atomic  conditions,  may 
have  its  cause  in  the  laws  of  the  reciprocal  action  of  atoms — that 
is,  in  the  difference  between  the  forces  exerted  upon  each  other 
by  atoms  according  to  the  different  relations  in  which  they  may 
stand  towards  each  other.  The  cause  of  the  permanence  of 
some  atomic  states  and  of  the  want  of  this  permanence  in  others 
has  not  hitherto  been  recognized  in  the  laws  of  the  reciprocal 
action  of  atoms ;  and  it  would  doubtless  be  difficult  to  succeed 
in  discovering  this  cause  in  such  laws  of  reciprocal  action  as  it 
has  hitherto  been  attempted  to  establish  and  to  assume  for  pon- 
derable atoms. 
The  question  consequently  presents  itself,  whether  the  cause 
of  the  permanence  of  certain  atomic  states  may  not  perhaps  be 
found  in  such  laws  of  mutual  action  as  have  here  been  esta- 
blished and  assumed  for  electrical  particles.  Hence  the  move- 
ments of  two  electrical  particles  under  the  influence  of  the  re- 
ciprocal action  assigned  to  them,  which  have  been  followed  out 
in  the  preceding  sections,  are  of  interest  in  connexion  with  this 
point  also,  since  in  them  a  cause  has  been  really  discovered  upon 
which  the  existence  of  such  permanent  states  of  aggregation 
may  be  founded.     And  in  relation  to  this  it  is  to  be  specially 
Phil.  Mag.  S.  4.  Vol.  43.  No.  284.  Feb.  1872.  K 
