Surveying instruments, a sum, and military devices
Leveling tools and 8 x 64 = 512 on sheet 902a; scythe, dart, sling and a bombard on 902b
Two sheets mounted together (902a and 902b recto) carry a miscellany of instruments and martial devices. On 902a are tools for leveling, lettered t, f and m, and a quick sum giving 8 x 64 = 512. Sheet 902b gathers a bladed instrument with a scythe, a dart and sling, a central aiming machine and, in the lower corner, a note on shot buried in a bombard likened to the squirt children make from plum twigs. Many further faint sketches surround these captioned items.
On this page
Instruments for leveling (labels t, f, m)
Sheet 902a bears surveying and leveling instruments, one group marked with the letters t, f and m. Such tools set out a horizontal line for measuring differences of level on the ground. The transcription gives only the labels, and further untranscribed sketches surround them.
A worked multiplication, 8 x 64 = 512
A short arithmetical operation is noted beside the drawings: the numbers 64, 8 and 512. Read together they give 8 x 64 = 512 (equivalently 8 cubed). The figure appears jotted as a quick calculation.
Aiming machine at the centre
At the centre of sheet 902b is a machine for aiming, drawn among the other devices on the sheet. It sits close to a large toothed-wheel mechanism. The transcription supplies only the label.
Instrument with a scythe
At the top of sheet 902b is a bladed instrument fitted with a scythe. It sits among a group of small military and mechanical sketches. No further text describes it.
Dart and sling
Below the scythe instrument Leonardo sketches a dart and a sling (frommola). These are hurled or hand-thrown projectile devices. Only the caption identifies them.
Bombard with buried shot
In the lower left corner Leonardo notes shot buried in the ground and lodged inside the bombard, and compares the effect to the little squirt that children make with plum twigs. The note pairs a gunnery observation with a homely simile. A bombard is drawn nearby.