THE DOMAIN OF PHYSICS. 5 



cal change is one that does change the identity 

 of the -molecule. 



(a.) If the piece of marble be acted upon by sulphuric acid, a 

 brisk effervescence takes place caused by the escape of carbonic acid, 

 gas which was a constituent of the marble ; calcium sulphate 

 (gypsum), not marble, will remain. The water may, by the action 

 of electricity, be decomposed into two parts of hydrogen and one of 

 oxygen. The nature of the glass and iron may easily be changed. 

 These change the nature of the molecule ; they are chemical 

 changes. 



12. Definition. Physics, or Natural Philos- 

 ophy, is the branch of science that treats of the 

 laws and physical properties of -matter, and of 

 those phenomena that depend upon physical 

 changes. 



Recapitulation. To be reproduced and amplified 

 by the pupil for review. 



Matter. Divisions. Attractions. Motions, 



r MASSES, GRAVITATION. 



PHYSICAL 

 SCIENCE. 



PHYSICS \ <Heat. 



MOLECULES, 



j COHESION. | J Light. 

 \ ADHESION. ) j Electricity, 

 \ Magnetism, 



f CHEMISM . 



CHEMISTRY. ATOMS \ OR [ (?) 



I AFFINITY. 



CHAFFS PHYSICAL - 

 CHANGES. 



