THE FUTURE OF SCIENCE IN OUR SCHOOLS 437 



into the rusting of iron, passing from this to the study of 

 combustion in so far as is necessary to establish the existence 

 in air of a constituent which is participant in such changes, 

 which combines with metals to form earthy substances. I 

 would advise that limestone be taken as the next subject of 

 study and after this common salt, beginning with sea-water. 

 Again I may refer you to suggestions I have made elsewhere 

 as to the manner in which the problems these substances 

 present may be treated. 



I would lay particular stress on the importance of the 

 thorough mastery of a single substance such as limestone, as 

 its properties are typical of those of salts generally, including 

 the rock-forming silicates ; moreover, the properties of its two 

 constituent oxides are equally typical of the two classes of 

 oxides — the acidic and the alkylic. If once the method of 

 arriving at the composite nature of such a substance be grasped 

 — if the learner be duly seized with understanding of its pro- 

 perties in relation to those of its constituent oxides and 

 elements — lessons of abiding value will have been learnt and 

 a very fair appreciation of the problems which confront the 

 chemist will have been gained. But to secure this end the 

 work must be done, not only with utmost deliberation and 

 understanding but exactly and with complete honesty of 

 purpose — by the pupil. 



The connecting link between chemistry and physics will be 

 established when the interaction of a metal such as zinc and 

 an acid such as chlorhydric or sulphuric is studied so as to 

 make clear the conditions which determine the occurrence of 

 chemical change and the essentially electrolytic character of the 

 process. The simpler phenomena of the electric current may 

 then be made the subject of inquiry. Energy and efficiency 

 may afterwards come under consideration, in order that a sound 

 knowledge may be acquired of the fundamental principles 

 underlying the use of the steam engine, the internal combustion 

 engine and the dynamo. 



When, in examining salt, the discovery is made that spirit 

 of salt is a composite gas and its composition is determined, 

 opportunity is given to discuss the kinetic theory of gases, the 

 existence of molecules and atoms, the determination of molecular 

 weights and subsequently of atomic weights as distinct from 

 equivalents. The meaning of formulae may then be made clear 



