The Child's Book of Nature for the Use of Families and Schools Intended to Aid Mothers and Teachers in Training Children in the Observation of Nature. Revised Edition. Part 3: Air, Water, Heat, Light, etc. (1886)
Hooker, Worthington · Harper & Brothers · leaf 77
AND BUBBLES. The hot-air balloon. How soap-bubbles are like balloons. relief, and took him on board. As such dangers attend going up in balloons, it is not very wise for any one to do it. You can fill a balloon with common air so as to make it fly up like the gas balloon ; but the air must be… … the air will keep heated longer. It is because heated air is so much lighter than the air around it that a balloon filled in this way goes up; but such a balloon comes down soon. It will not keep up so long as a gas balloon will. Why is this ? It is because the heated air in the balloon becomes…
