Calendar: 1893-1894 Page 891

SCIENCE AND SAMBROOKE EXHIBITIONS clxxiii string of india-rubber is stretched by force of 21bs and it executes transverse vibrations per second The length is halved and the stretching force increased to lbs What is now the frequency of the vibrations Two equal small balls one having positive change of 10 units and the other negative charge of units are cm apart what is the attractive force between them If they are made to touch and again separated by the same distance what will be the force of repulsion Enunciate Ohm's law The external resistance in certain circuit is two-thirds that of the battery what change will be produced in the current by reducing the external resistance to half its former value What do you understand by the chemical equivalent of metal How may this differ from the atomic weight of the same metal Give an instance of metal in which the equivalent and the atomic weight are the same and one in which they differ How may Ozone be formed What evidence can you mention showing that the molecule of ozone may be regarded as containing three atoms of oxygen Phosphine gas may be obtained by the interaction of phosphorus water and barium or potassium hydroxides express both the reactions in chemical formulae Mention some of the most characteristic properties of the gas Illustrate by chemical equations the action of hydro- chloric acid on the following substances respectively Cu20 Fe203 Sn02 Sb203 and Cr03 Describe what you know of the oxides and oxy-acids of antimony Point out any elationships which may exist between the acids of antimony and their salts and those of nitric and phosphoric acid