512 REPORTS ON THE STATE OF SCIENCE. 



flask with an air pump, (6) by boiling a small quantity of water in the flask. 

 Definition of density as the weight of unit volume of a substance. 



Floating bodies ; reference to earlier experiments with cubes of wood, some of 

 which float and others sink^ to show that bodies heavier than water sink in water 

 and others float ; an egg suspended midway in a brine solution is neither heavier 

 nor lighter than the brine ; calculation of the weight of one cubic centimetre of 

 the egg. .... 



Experiments to show that a floating body displaces its own weight of water, 

 and to find the fraction of its volume immersed in water. Construction of hydro- 

 meter to measure dilution of milk with water. 



Application of the laws of floating bodies to ships ; why ii'on ships float. 



Familiar examples of apparent loss of weight of bodies in water; refer to 

 carriage of rocks and stones by rivers ; the diver works under water loaded with 

 lead; experiments with bodies of known volumes weighed in air and water; 

 discovery of law of Archimedes ; increase in weight of a vessel of water when a 

 body is suspended in it from an external support. 



Use of the law of Archimides for finding the volume of irregular bodies 

 heavier than water ; calculation of the weight of one cubic centimetre of these 

 bodies. 



Show that this method of finding volume, since it depends on the use of the 

 balance only, is more accurate than any previously employed. 



General effects of heat on animal and vegetable matter ; wood and coal heated 

 in hard glass tubes give off" inflammable gases which burn in air. The char of 

 carbon left in the tube will not burn until heated in air ; air evidently necessary 

 to charcoal burning. When it is completely burnt a light mineral ash is left. 

 Carefully dry some finely divided animal and vegetable matter and determine 

 percentage of water. The water in foods does not provide nourishment ; the com- 

 bustion of foods produces heat. 



Notice effects of strongly heating weighed quantities of sand, granite, lime- 

 stone, iron, copper, magnesium, &c. Some do not change, some lose weight, and 

 some gain weight. 



Expansion of solids, liquids, and gases shown qualitatively. Applications of 

 expansion by heat to method of fixing metal tyres on wheels, riveting, circulation 

 of hot water, ocean currents, winds, draughts, and ventilation. 



Hotness or temperature measured by expansion of liquids. Distinction between 

 heat, which is energy and possesses the power of doing work and producing change, 

 and temperature or hotness, which is the intensity of heat; analogy with quantity 

 and pressure of water or gas. Definitions of unit of teinjyei-ature (degree Centi- 

 grade) and unit of heat (calorie or gram degree Centigrade unit). Comparison of 

 times taken to raise large and small quantities of water to the same temperature 

 by the same source of heab. Amount of heat depends on quantity of material 

 heated. 



Construction of spirit thermometer; graduation of thermometer for household 

 purposes. The eflPect of large masses of warm water round the coast of British 

 Islands on its climate. 



The freezing of water ; ice always formed at the surface ; ice will float ; find 

 density of ice by making a mixture of spirit and water in which a lump of ice 

 remains suspended ; find the weight of 1 c.c. of the mixture. The reason why 

 water freezes at the surface ; economic impoitance of the fact. Applications of 

 the increase of volume of water when freezing to bursting of water pipes, to the 

 breaking up of the soil in winter, to the spliting of rocks, &c. 



The boiling of water; steam and water vapour both invisible gases; the nature 

 of cloud, dew, frost, rain, snow. The boiling-point of water varies slightly with 

 the ordinary changes in barometer, and very considerably at great altitudes or 

 depths. 



Determine whether a number of familiar substances are soluble, partially 

 soluble, or insoluble in water. Filtration as a means of separating soluble from 

 insoluble bodies. Distinction between dissolving and melting, as illustrated by the 

 solution of sugar in water and the melting of sugar by heat. 



