Fortification scheme, colliding spheres, and a maxim on artillery
A crowded sheet: a lettered fortification plan, the unequal impacts of two balls, and reciprocity of attack and defence.
This crowded sheet mixes military, structural and mechanical studies. A lettered scheme (d b a – g c – f e) sets out a plan of fortification, while an inverted note in the lower margin gives the maxim that one should not be vulnerable through the same openings by which one attacks, since artillery can enter along the very line by which it fires. Elsewhere Leonardo observes that the proportion of two colliding balls is not equal to the proportion of the impacts they make. Prominent among the drawings are a centralized domed pavilion with a fan-vaulted canopy and numerous small plans and mechanisms; further untranscribed notes accompany them.
On this page
Fortification scheme with lettered points
A structural scheme of fortification labelled with the sequence d b a – g c – f e, drawn with the sheet turned onto its left side. The lettered points mark positions in the plan.
Domed pavilion with fan-vaulted canopy
A centralized domed structure crowned by a spreading, fan-vaulted canopy is drawn at the upper left. No transcription accompanies this drawing, so it is noted from the image alone; further untranscribed notes are present nearby.
Two spheres in contact and their unequal impacts
Two balls, labelled a and b, are shown in contact. Leonardo notes that the proportion of the two balls is not equal to the proportion of the two impacts (percussions) that they make.
Maxim on the reciprocity of attack and defence
Written inverted along the opposite margin: from as many places as you attack, take care you are not attacked through those same places. It cannot be avoided that, along the line by which artillery goes out, a similar or smaller artillery does not enter.
Small plans and mechanisms
The lower half of the sheet is filled with small mechanical sketches and plan diagrams. These carry no transcribed text and are noted here only from the drawing.