On impression: soldering and smoothing curved copper plates
A press and planing bench for shaping laminae over a stone mould, with a letter fragment.
Under the heading 'On impression', Leonardo describes forming and joining large curved metal plates. Copper ('Venus') is drawn out a palm wide, fixed on the stamp as pieces a b c, pulled by successive levers, soldered in a pyramid, then beaten with a wooden hammer and reheated over coals, the male form being a dense stone six or eight braccia across. A separate apparatus polishes the wood over a template b that slides in a narrow transverse channel n m, the rubbing done with lead and emery on copper. A geometric note on arcs of different radius shows that a smaller semidiameter (c b) describes a smaller circle than c a; a stray line in the left margin begins a personal letter, 'Dearest friend, I inform you how...'.
On this page
Soldering copper plates over a stone form
Copper is drawn out a palm in width and fixed on the stamp as pieces a b c, pulled by various levers one after another and soldered together into a pyramid, then beaten again with a wooden hammer while being reheated over a bed of coals. The male form is of marble or other dense stone, made six or eight braccia in diameter and perfected by burnishing.
A bench for smoothing plates with a sliding template
b is the template; n m is the transverse channel in which it moves, and the narrower m n is made, the straighter and truer the wood running above b travels. The rubbing is carried out with lead and emery upon copper.
Arcs described by different radii
The circle with the smaller semidiameter has less motion; thus the semidiameter c a describes a greater circle than c b. For this reason the strip is narrower at the foot than at the head.
Fragment of a personal letter
Halfway down the left margin a single line breaks off from the technical notes and begins a letter: 'Dearest friend, I inform you how...'. Nothing further of the message is transcribed here.