490 REPOETS ON THE STATE OF SCIENCE, ETC. 



C. General Physics. 



1. How ships float. Measurement of extra displacement produced by adding 

 ' cargo ' to a box floating in water suggests Archimedes' Principle. Confirma- 

 tion in case of other liquids. Extension of principle to bodies that sinli. Use 

 of camels and pontoons. Submarine boats. Balloons and airships ; contrast with 

 aeroplane. 



Exercises on use of Archimedes' Principle in determining volumes and specific 

 gravities. 



2. The barometer as a meteorological instrument. Construction of siphon 

 barometer. Pascal's theory of action illustrated by demonstrating increasing 

 pressure at lower depths in a jar of water. The experiment of the Puy de 

 Dome. Reduction of barometer readings to sea-level for construction of 

 barometric charts. Relation between isobars and 'winds. 



Boyle's experiments in confirmation of Pascal ; leading to notion of the 

 ' spring ' of the air and to Boyle's Law. 



Experiments and apparatus illustrating air-pressure : pumps, vacuum-brake, 

 parcel-transmitter, siphon, &c. The aneroid barometer : its use in determining 

 heights in mountaineering, aeroplaning, &c. 



Archimedes' Principle explained by theory of liquid-pressure. The theory 

 applied to explain water-supply systems, hydraulic lifts and engines. 



3. Capillarity. Experiments to supplement those of I., C, 1. Measurement 

 of surface tension (in grams-weight per cm.) by rise of water in tube. Simple 

 study of bubbles, drops, and jets; also of common phenomena such as writing 

 with ink. 



4. Osmosis. Simple experiments to supplement I., C, 1. Passage of dis- 

 solved salts through a porous partition until equality of concentration is set up. 

 Use in purifying beet-molasses. Semi-permeable membranes ; law of osmotic 

 pressure ; comparison with Boyle's Law for gases. Application to plant-cell. 



5. Revision of work of First Year, II., B., 2. Use of spring balance to 

 measure a ' force ' (i.e. a push or a pull) in terms of weight. Hooke's Law in 

 the stretching of strings, the bending of beams, &c. Use of a single (rough) 

 fixed pulley; measurement of its 'efficiency.' Use of movable pulleys. The 

 Principle of Work introduced for the determination of their efficiency. 



Loss of work by friction ; simple laws of friction. 



Application of Principle of Work to lever, to haulage on an incline (without 

 and with friction), &c. 



6. Conditions of equivalence of a single force {e.g. a pull in a cord) to two 

 others. The vector law. Applications : the suspension bridge, cantilever 

 frames, &c. 



D. Heat. 



1. Revision of First Year work. Mean temperatures in meteorology ; regu- 

 larity of mean seasonal changes over long periods. Geographical isotherms. 



Temperatures at high altitudes and at great depths in sea. 

 Dependence of boiling and freezing points on pressure ; regelation, skating, 

 snowballs. 



2. Hot-water circulation; convection. Function of radiators. Loss of tem- 

 perature through conduction. Experiments on and illustrations of convection . 

 radiation, and conduction : clothing, bark of trees, radiation from gravel and 

 vegetation, &c. ; thermostats, the thermos flask, temperature of ' Tube ' rail- 

 ways, &c. 



Curves of cooling of equal amounts of different substances (e.g. water and 

 Band) ; geographical importance of slow rate of cooling and heating of wator. 



Lagging of temperature at different depths below surface of soil. (To be 

 taken in connection with I., B.) 



3. Extension of First Year, II., C, 3; separation of liquids by distillation. 

 Applications : petroleum industry, turpentine and resin. 



Simple treatment of vapour pressure. 



Evaporation and condensation. Precipitation of rain and dew. Simple 

 hygrometry ; determination of dew-point ; relative humidity. Wet and dry 

 bulb thermometer. 



Cold produced by evaporation. Ice-making, cpld storage. 



