496 REPORTS ON THE STATE OF SCIENCE, ETC. 



including the earliest appearances of man (cf. 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 formulae y = cL sin — (x±rt) 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 nioving 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 torque = 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 : 



(fl) 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 cf 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 ampere in terms of silver 

 deposited per second. Congruence with measurement in terms of deflection in 

 tangent galvanometer. 



((■) 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 l/v + l/u = l/ f ; 

 experimental verification. 



{b) Lenses: experimental discovery of the formula UV = /^; deduction from 

 this of the formula 1/u-1/m = 1//. Magnification; telescopes, microscopes; 

 the prismatic field-glass. Achromatic lenses. The lens of the eye and its 

 optical defects ; spectacles. 



(r) Methods of determining the velocity of light. 



3. Wave-motion in sound, light, and electricity. 



(a) 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. 



(b) The undulatory theory of light. Colours of thin films, interference; 

 diffraction ; polarisation. Deduction of behaviour of mirrors, prisms, and lenses 



