21.(Pg. [123]) How by the apparatus represented at [fig. 6, plate 13]?

22.(Pg. [123]) What is meant by the specific gravity of a body?

23.(Pg. [123]) What do we in common mean by calling a body heavy, or light?

24.(Pg. [124]) Why would not the metals answer to compare other bodies with?

25.(Pg. [124]) What must be supposed equal in estimating the specific gravity of a body?

26.(Pg. [124]) What has been adopted as a standard for comparison?

27.(Pg. [125]) What is the first step in ascertaining the specific gravity of a solid?

28.(Pg. [125]) What quantity of water will the solid displace?

29.(Pg. [125]) Why will a solid weigh less in water than in air, and to what will the loss of weight be equal?

30.(Pg. [126]) What is the arrangement represented by [fig. 7, plate 13]?