Calendar: 1880-1881 Page 668

668 APPLIED SCIENCES Explain the action of the common suction pump the air pump State Boyle's law Two centimetres of air are measured off at atmospheric pressure When introduced into the vacuum of barometer they depress the mercury which previously stood at 30 inches and occupy volume of 15 cubic centimetres By how much has the mercurial column been depressed ball of iron and ball of brass each 10 inches in radius are suspended by strings and immersed to the same depth in water at so that their nearest points are -th of an inch apart To what temperature must the water be raised so that the two may just touch The coefficient of linear expansion for is for iron Ό00012 and for brass 000019 Describe Regnault's apparatus for determining the pressure of vapour of water at different temperatures Give an account of Black's determination of the latent heat of ice One pound of ice at and three pounds of water at 79 are mixed together find the temperature of the mixture Compare the weight of cubic centimetre of air at 10 and under pressure equal to that of 350 mm of mercury with the weight of 10 cubic centimetres of air at temperature of 100 and under pressure equal to 700 mm of mercury Prove that the intensity of radiant heat varies inversely with the square of the distance from the source of heat and describe two methods of experimentally demonstrating this law IV -fHedjamtf SECOND AND THIRD YEARS beam feet long and weighing lbs balances by itself about point feet from one end If weight of 20 lbs be hung foot from this end find the weight that must be hung from the other extremity that the beam may balance about its middle point