1. For a tracing and a discussion of these drawings, see Pedretti C., The literary works of Leonardo da Vinci edited by J. P. Richter: A commentary (Oxford, 1977), ii, 133–4.
2. Ibid. § 902, Plate CVIII, no. 5. See also the recent exhibition catalogue by Roberts J. and Pedretti C., The Codex Hammer of Leonardo da Vinci (Palazzo Vecchio, Florence, 1982), fol. 2A (2r), with full bibliography, 126.