Show weighty air the ancients considered air an imponderable substance but in the past years our knowledge of it has increased considerably one au dhority says london tit bits maga zine says that the air in the average room weighs about pounds A cubic foot weighs as much as a letter which can be sent through the post tor for 1 pence and in the course of a day the weight of air breathed by the average person is greater than the weight of food con burned by him air is composed of more than a dozen gases which in elude nitrogen oxygen carbon dioxide water vapor hydrogen helium neon argon krypton xenon radon and other lesser known ele ments |