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- Tat. No #hysical explanation of the origin or formation of these bodies has yet been found. Some have supposed them to arise from terrestrial volcanees; others from those of the moon; while modorm chemists have supposed them to be concretions formed in the air. . . .
. . . . DIALOGUE III. * ..." ofthe Air, Wind, Vapour, Rain, &c. Pup. I often hear of the air; what idea am s to fărim of that which is invisible % Tat. It is a fluid which agitates bodies when it is its motion. It has the properties of rarity, transparentor, and elasticity ; and when compressed, has to himazing power, very similar to that of gunpowder, and carries aii before it. $ - , Pup. Has the air any. other peculiar propęrties ? ...Tut, it conveys sound, and it is uecessary to give us the sense of hearing: without air, we should have no music, no sidell ; nor should we be able to live or converse with each other. Were it not also for the air, which abounds with particles capable of reflect. ing light in all directions, only that part of the heavens would appear bright in which the sun is situated, and "the stars and planets would he wisible' at mid-day. • • Pup. £fòw is air divided? . -.*, ... ■• • . . Tut. Into vital and atmespheric. } Pup. What are ' the conapqnent, parts of . atmospheric air? - Tut. Of 100 parts, twenty-one are vital and seventy-nine poisonous. '***' ' ' ' Pup. How much lighter is air than water?
