The Roman Harbour of Civitavecchia
Ashlar blocks, layered mosaic pavements and porticoes of the Roman mole
This leaf records Leonardo's observations of the ancient Roman harbour of Civitavecchia. He notes the great ashlar blocks facing the mole (4 by 2 1/2 by 2 1/4 braccia) and describes, with lettered diagrams a-b-c, how the imperial chambers' floors were built up in layers of lime, tufa chips, gravel and brick and finished with coloured mosaic, fronted by column porticoes and steps running down to the water. Compass constructions, a quarter-arc and a radially divided circle, and a stone-block sketch occupy the upper and right-hand parts of the sheet.
On this page
Ashlar blocks facing the Civitavecchia mole
A drawn stone block is given as 4 braccia long, 2 1/2 wide and 2 1/4 thick, which Leonardo says is the size of the stones set in the fronts of the mole of the port of Civitavecchia. A separate detail below is captioned as half a braccio and labelled the front of the port wall.
Imperial chambers, portico and sea-steps
The pavements described belong to the imperial chambers built upon the mole of the port; before these chambers stood porticoes with thick columns to which ships were tied, and before the portico ran nine flights of steps down to the water, equal to 3 braccia.
Layered lime-and-mosaic pavement (a, b, c)
The square a, ten wide and twelve long and half a braccio deep, is walled with lime and chips of tough spongy tufa and plastered with lime and sand; the cavity is filled with coarse gravel, then a cast of lime and small brick, and finally the mosaic of coloured stones with designs and foliage. The construction is keyed to the letters a, b and c on the three drawings.
Compass arc and sectored circle
The right half of the sheet carries compass work: a large quarter-circle arc and a circle divided by radial lines into sectors, drawn faintly across the otherwise blank space.