Air to Lift Weights, and Water Falling from a River
Buoyancy and enclosed air compared: rarefied, common, and condensed
Leonardo poses a set of questions on the sustaining power of air and water: how much air is needed to lift weights of various materials, how much water entering a boat will sink it, and which enclosed air sustains most weight. He concludes that rarefied air (as in cupping glasses) sustains most, then common air, while condensed air (as in screw-inflated balls) resists least. A second note states that each part of water falling from a river keeps the line in which its impetus began; streaming forms drawn at the right depict this falling water.
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Which enclosed air sustains the most weight
How much air is needed to lift weights of different materials, and how much water will enter a boat to sink it? Of enclosed air, the rarefied (as in cupping glasses) sustains most, then the common air, while the condensed air (as in balls inflated by force of a screw) resists least.
Falling water keeps its initial line of impetus
Each part of the thickness of water that falls from a river into the air follows the line in which the impetus that carried it in the fall was begun. The streaming figures at the right illustrate this trajectory.