SCIENCE IN SECONDARY SCHOOLS. 171 
including the earliest appearances of man (ef. I., 2); (ii) special subjects 
of geographical importance, e.g. the coal age and the ice age, ‘block’ and 
‘fold’ mountains, rifts and faults; (iii) questions of economic geology selected 
on the ground of either local or national importance. In connection with 
(i) visits should be made to a geological museum, and holiday collections of 
fossils encouraged by the School Science Club. 
B. Mechanics. 
1. Revision of work of Second and Third Years; straightforward problems 
on motion and equilibrium to give a firm grasp of principles. 
Rate of doing work; horse-power; dynamometers. Work of engines in road, 
rail, and water traffic. Economy of power. 
Simple theory of the aeroplane. 
2. Circular motion. Harmonic motion of pendulum, vibrating spring, &c. 
Connection with Hooke’s Law (Second Year, II., C., 5). 
The formule y=a sin Zs (w+vt) as descriptive of progressive harmonic 
waves. Stationary waves. Wave-motion as a mode of transmission of energy. 
3. The principle of energy in the case of a thin cylinder rotating about its 
axis while the latter is moving parallel to itself. Determination of ‘g’ by 
measuring time taken by such a cylinder to roll down a sloping plane. 
Derivation of the principle of Conservation of Moment of Momentum, and 
of the formula torqgue=rate of change of moment of momentum. Applications 
to phenomena of bicycling, spinning tops, gyroscopes, &c. Moment of inertia 
and radius of gyration in simple cases. Motion of a rod struck at a given 
point. Harmonic vibration of a compound pendulum and of a horizontally 
suspended magnet. Inversion of compound pendulum; ‘ centre of percussion.’ 
C. Physics. 
1. Electro-magnetic measurements : 
(a) Distribution of magnetism along a bar-magnet. Magnetic fields; lines 
of force; use of small compass-needle to map field near magnet or current 
circuit. 
Deflection of small compass-needle by magnet; the tangent law; application 
in the tangent galvanometer. The moment of a magnet. 
(6) Chemical equivalence of substances liberated by a current passing 
through electrolytic cells in series. Definition of the ampére in terms of silver 
deposited per second. Congruence with measurement in terms of deflection in 
tangent galvanometer. 
(c) A long platinoid wire is ‘tapped’ by the terminals of a high-resistance 
galvanometer. The results lead to the notions of a regular ‘fall of potential ’ 
and of the connection of potential difference with current-strength and 
resistance. Definition of the ohm and the volt. Ohm’s law. 
(d) Quantitative statement of Faraday’s law of induction. The earth- 
inductor; the transformer. Magnetic force and magnetic induction in iron; 
permeability ; hysteresis. 
2. Optical measurements and calculations. 
(a) Spherical mirrors; theoretical derivation of the formula 1/v+1/u=1/f; 
experimental verification. 
(6) Lenses : experimental discovery of the formula UV=/?; deduction from 
this of the formula 1/v—1/u=1/f. Magnification; telescopes, microscopes ; 
the prismatic field-glass. Achromatic lenses. The lens of the eye and its 
optical defects; spectacles. 
(c) Methods of determining the velocity of light. 
3. Wave-motion in sound, light, and electricity. 
(az) General properties of harmonic wave-motion, longitudinal and _ trans- 
verse (to be taken in connection with B., 2). Application to elucidate the 
behaviour of sounding forks, strings, and pipes. Free and forced vibrations; 
resonance. 
(6) The undulatory theory of light. Colours of thin films, interference; 
diffraction ; polarisation. Deduction of behaviour of mirrors, prisms, and lenses 
