of  Thermodynamics,  in  reply  to  Prof.  Clausius.  517 
in  the  Dissipation  of  Energy.  And,  though  I  gladly  comply 
with  his  desire  to  leave  to  future  generations  the  value  of 
"  innere  Arbeit"  and  of  " Disgregation,"  I  should  much  like  to 
know  in  what  respect  the  former  term  is  an  improvement  on 
the  name  "  Latent  Heat ,J  which  was  given  by  the  discoverer 
himself. 
But  I  think  it  would  be  a  pity  to  leave  to  the  future  the  dis- 
cussion of  the  other  point  at  issue,  since  so  much  depends  upon 
Professor  CJausius's  interpretation  of  his  own  words.  The 
question  is,  "  Who  first  correctly  adapted  Carnot's  magnificently 
original  methods  to  the  true  Theory  of  Heat  V  Nothing  was 
wanting  for  this  but  a  sound  Axiom  :  the  method  was  already 
provided;  and  the  brothers  Thomson  had  (in  1848  and  1849) 
recalled  it  to  the  attention  of  the  scientific  world  (Professor 
Clausius  included)  by  deducing  from  it  an  absolute  definition 
of  temperature,  and  the  effect  of  pressure  upon  the  melting- 
points  of  solids. 
Now  it  is  one  thing  to  rush  into  print  with  a  proof  which 
has  afterwards  to  be  explained  and  patched  up,  and  quite  an- 
other thing  to  wait  till  one  hits  on  a  complete  and  irrefragable 
demonstration. 
The  following  are,  as  far  as  I  can  see,  the  words  to  which 
Professor  Clausius  refers  as  implicitly  containing  his  Axiom, 
which  is  nowhere  explicitly  stated  in  his  first  paper.  They  do 
not  contain  the  phrase  "von  selbst,"  to  which  he  assigns  so 
important  and  extensive  a  meaning.  "Durch  Wiederholung 
dieser  beiden  abwechselnden  Processe  konnte  man  also,  ohne 
irgend  einen  Kraftaufwand  oder  eine  andere  Veranderung,  be- 
liebig  viel  Warme  aus  einem  kalten  Korper  in  einen  warmen 
schaffen,  und  das  widerspricht  dem  sonstigen  Verhalten  der 
Warme,  indem  sie  iiberall  das  Bestreben  zeigt,  vorkommende 
Temperaturdifferenzen  auszugleichen und  also  aus  den  w'drmeren 
Korpern  in  die  kdlteren  uberzugehen."  I  still  fail  to  reconcile 
this  with  the  thermoelectric  phenomena  to  which  I  referred,  in 
which  certainly  part  of  the  heat  has  the  very  opposite  "  Bestre- 
ben M  to  that  which  Professor  Clausius  assumed  to  be  universal. 
And  I  think  that  Thomson  has  done  mischief  as  regards  scien- 
tific history,  by  giving  Professor  Clausius  undue  credit,  and 
unwarrantably  representing  these  words  as  containing  the  Axiom, 
"  It  is  impossible  for  a  self-acting  machine,  unaided  by  any  ex- 
ternal agency,  to  convey  heat  from  one  body  to  another  at  a 
higher  temperature."  Moreover  Thomson  is  certainly  mistaken 
when  he  asserts  that  even  this  is  equivalent  to  his  own  Axiom. 
P.S. — I  have  just  seen  the  4th  Heft  of  PoggendorfFs  Annalen, 
recently  published.     I  shall  probably  refer  more  in  detail  (on 
