APPENDICES 



APPENDIX I 



LECTURE ON JOHN DALTON 



(Delivered to the boys of Eton College) 



Two marble statues are placed one on each side of the 

 entrance to the magnificent municipal buildings in the City 

 of Manchester. They are not statues of merchant princes or 

 even of men who have successfully applied science to manu- 

 facture or industrial enterprise, and thus won for themselves 

 great wealth. They are statues of men who, poor in worldly 

 goods, were rich in fame and genius, and who, by benefiting 

 others rather than themselves, have contributed more to the 

 extension and development of commerce, industry, and 

 civilisation, than perhaps any other two men of the nineteenth 

 century. 



Thus honour is done to Manchester's two greatest sons, to 

 Dalton, the founder of the Atomic Theory, and to Joule, the 

 discoverer of the Law of the Conservation of Energy. It is 

 to Dalton that we owe the final and absolute proof that 

 matter cannot be destroyed ; that all the chemical changes 

 which we observe are simply the passage of one form of 

 matter into the other, often from the visible to the invisible ; 

 whilst to Joule we owe the foundation of the principle that in 

 all the various modes of chemical and physical change no 

 loss of energy takes place. That is to say, just as we cannot 

 create or destroy matter, so also we cannot create or destroy 

 energy. When the candle burns and the wax disappears its 

 constituents are not lost, but escape in the form of steam and 

 carbonic acid gas, formed by the union of the hydrogen and 

 carbon of the wax with atmospheric oxygen ; so the energy of 

 the chemical forces locked up, or potential, in the wax and in 



