Back-eddies that lay down earth, with sums and a cart part
Folio 128r: a red-chalk study of whirling eddies, a column of figures, and a wagon component
At the top the sheet carries a red-chalk column of figures (150, 40, 000, 6000). Below, a coiled form drawn in sanguigna illustrates back-eddies, glossed by the note 'I pigri retrosi pongan terreno' - the sluggish back-eddies lay down earth (sediment). At lower right a stand with two upright arms is captioned as part of a cart. Further faint chalk marks are present but are not transcribed in the bundle.
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Sluggish back-eddies deposit sediment
The note observes that slow-turning back-eddies (retrosi) lay down earth, an early remark on how eddying water drops the sediment it carries. The adjacent coiled red-chalk form illustrates the whirling motion of such an eddy.
Column of red-chalk figures
A short vertical column of numbers is set out in red chalk near the top of the leaf: 150, 40, then 000 and 6000. The arrangement suggests a running calculation or sum.
Part of a cart
At lower right a small structure with two upright, horn-like arms rising from a base is sketched in red chalk. It is identified in the catalogue as a component of a cart.