Propositions on gravity, descent and the density of bodies
Two columns of laws of weight, with margin notes on density and a passage on water, vapour and clouds
This densely written sheet gathers a series of aphoristic laws of gravity and motion in two facing columns: every heavy thing seeks the centre by the shortest path, the less oblique motion makes a body weigh more and descend faster, impetus carries weight beyond its natural place, and the more united a gravity the more it weighs. The left margin adds observations that pressure and cooling increase density (in bronze, beaten metal, pressed earth, stone and wood), concluding that no body can be made perfectly round. A lower passage, tied to sketched balances, argues the unity of weight through water that evaporates into vapour too fine for a cord to hold, clouds sustained by air until their particles recompose into raindrops, and compressed versus spread cotton.
On this page
Right column: laws of descent and weight
Every heavy thing strives that its centre be equidistant toward the lighter elements; that weight becomes greater which has less resistance, and the more it descends the more it grows. Every heavy thing that descends freely directs itself to the centre by the shortest way, and the less oblique motion shows a greater heaviness. The heavier part of bodies makes itself, in all motions, the guide of the lighter.
Left column: centre of gravity and impetus
A body shows itself heavier which is resisted with less power, and the more it falls the more impetus it acquires. The centre of gravity of bodies will not be equidistant to their extremities, and the centre of quantity will never coincide with the centre of gravity; the less oblique motion becomes swifter, and the more it descends the more it weighs.
Left margin: density from pressure and cooling
The part of bronze that falls first while liquid becomes denser and heavier; beaten metal nearest the blow becomes denser, and earth or paste nearest the pressing hand condenses more. Stone is not of uniform material, the part nearest the air being denser, and wood turned toward the south is denser; no body can be made of perfect roundness.
Unity of weight: water, vapour, clouds and rain
The more united the gravity, the greater its weight: water united together composes a definite weight, but heated it goes off in smoke so subtle that the air alone sustains it. So too clouds of thin mist are held up by the air until their smallest particles cling together, recompose droplets, and then weigh and rain; and cotton bound tight to weigh a pound weighs almost nothing when spread like an inflated bladder.