504 REPORTS ON THE STATE OF SCIENCE, ETC. 



Theories of the origin of the solar system, the history of the earth and its 

 movements, may lead naturally to a discussion of the seasons, of early modifi- 

 cations of the earth's crust, and of the great wind belts. 



Such a course as this may run concurrently with a course of experimental 

 work on light, the two sets of lessons being constantly linked together. 

 Very simple experiments showing propagation of light in straight lines, 

 formation of shadows, reflection and refraction will lead on to the study of 

 the eye, and of optical instruments and their use in the observatory. Colour, 

 the wave theory of light, and means of measuring the velocity of light can 

 also be simply dealt with. 



IV. Ages 15 and 16. — During the last two years of the general school course 

 the pupils should be introduced to some of the theories which dominate 

 scientific thought at the present day. They should realise how great theories 

 grow — the industrious collection of data, the leap forward of some master- 

 mind to grasp the deeper truth which underlies and unifies the apparently 

 disconnected facts, the laborious process of verification, (a) The object of the 

 first term's work is to bring forward the wide conception that all forms of 

 energy are convertible one into another, and that the great mechanical devices 

 which have been invented are methods of converting the forms of energy into 

 the most useful kind for any special piece of work. It may also form an intro- 

 duction to the study of magnetism and electricity and show how the electric 

 power used in every-day life is generated. For example, it is quite easy to 

 measure the mechanical equivalent of heat, to show how chemical energy can 

 be used to generate electric energy, and to show how electric energy can cause 

 chemical change. In the study of the dynamo, magnetic and electric energy 

 can be shown to help each other and to produce heat, light, and mechanical work. 

 This will lead to a discussion of the working of electric trams, the production of 

 electric light, and of much else. (6) The object of this part of the course is to obtain 

 experimental results which lead on to an understanding of the general theories with 

 regard to the constitution of matter. 



The experiments can be made to develop in a logical sequence starting from 

 the study of air and the oxides. They can be carried out both qualitatively 

 and quantitatively, leading to the knowledge of the quantitative nature of 

 chemical action and also to the properties of many substances — e.g., acids, 

 alkalies, and salts. Equivalent weights of some of the elements may be found 

 by simple but accurate work. 



A possible arrangement of this experimental work is as follows : — 



1. Chemical changes caused by heating substances in air. 



2. Chemical changes due to heating substances out of contact with air. 



3. Chemical changes due to the action of substances on each other. 



When new substances are discovered their properties can be investigated and 

 the history of the discovery in many cases given. . 



An important bit of work which should not be omitted in a course of this kind 

 is the application of chemical properties of substances used in everyday life — e.g. 

 the softening of water, the preparation of explosives and fertilising agents, the 

 comparison of baking-soda and washing-soda, the manufacture of matches, &c. 

 But these will be side issues. 



But collection of experimental results and a discussion of the explanation of 

 these will give rise to an historical treatment of the molecular and atomic 

 theory Dalton's work being dealt with. The newer theories of the constitution 

 of matter and their bearing on the older theories may then be discussed. The 

 theoretical explanation of many results obtained in the early part of the course 

 now becomes evident, and facts which had hitherto appeared disconnected and 

 comparatively meaningless are suddenly seen to be intimately connected and 

 interdependent ; a new mental outlook is reached which both transforms the 

 view of knowledge already obtained and suggests fresh problems to attack. 



V. Ages 17 and 18. — No girl should leave school without some acquaintance 

 with the laws of health based upon a knowledge of the working of a living 

 body. It is preferable that this should be given at a late stage in the school 

 course, both on account of the greater maturity of mind and body which 

 has been attained, and also because sound elementary knowledge of physics 



