Letter, from Antoni van Leeuwenhoek to the Royal Society, dated at Delft Signed autograph Observations of the structure and texture of the shaft of a bird's feather as used in a quill; examination of the lens and cornea of the human eye and a calf; observations of 'wood-pipes' in different species of wood; engraver made drawings; observations of bulrushes; structure and texture of pine and lime wood No original figures; 20 engraved figures for publication are attached English translation see EL/L2/40 Transcribed and translated in 'Alle de brieven van Antoni van Leeuwenhoek', edited, illustrated and annotated by Committee of Dutch Scientists, vol 9, p 69 12 August 1692