Fortress Defences, a Domed Church, and a Suspended Beam
Night-watch rules and triple gateways, with notes on church roofs and load-bearing
The page mixes military and architectural studies. Leonardo prescribes how a fortress should be guarded, with rotating night-watches drawn by lot and hailed several times a night, and designs a triple-gated entrance in which two gates always stay shut; he also sections a round tower whose lowering bridge sits over an inner well, citing the bridges of the Castello of Milan. A large centrally-planned domed church is drawn in perspective with the remark that churches look best without visible roofs, water running off through channels in the frieze. A short mechanical note states that the centre of a suspended weight settles beneath its support.
On this page
Rules for the night-watch of a stronghold
The guards of the fortress are to be posted night by night so that no man knows in advance who his companion will be; each evening the assignments are drawn by lot on the spot. In times of suspicion they call to one another three times an hour, while in peacetime the round is done silently three or four times a night.
A central-plan church without visible roofs
Leonardo argues that no church looks well with roofs in view; the covering should instead be flattened. Rainwater is to run off through channels leading to conduits concealed in the frieze.
Centre of a suspended weight
A brief statics note attached to a hanging beam. The centre of every suspended weight establishes itself directly beneath its point of support.
A fortress with three gates (porta, porta, rastrello)
The fortress is to have three gates arranged so that two always remain shut as one passes. Entering the first portcullis, the two inner gates are closed; at the middle gate the portcullis and front gate stay shut; and at the last gate the middle gate and the portcullis are shut.
Section of a round tower with a bridge over an inner well
Marked with spans of 14 braccia and the letters b and A, the tower has a well (A) over which a bridge is lowered from b-A. Leonardo places the bridge inside the tower so a defender within cannot break the passage with a short cannon, a weakness he says could befall the bridges of the Castle of Milan shown to the right.