image EL_L3_05_Fig
Image number: RS.15796
Credit: ©The Royal Society

Observations on the cornea of a beetle, optic nerves of a drone fly and the brain of a gnat


9 May 1698


Unknown, Artist

Object type

Archive reference number

Manuscript page number




height (page): 200mm
width (page): 152mm



Five figures in a letter from Antoni van Leeuwenhoek to the Royal Society.

Fig. 1: part of the cornea of a beetle
Fig. 2: optic nerve of a fly
Fig. 3: seven optic nerves in a fly
Fig. 4: optic nerves in a fly
Fig. 5: the brain of a gnat.

Object history

According to the Journal Book, on 11 May 1698, 'A letter from Mr Lieuwenhoeck was read being an account of ye eyes of flies wherein he discovers that there are optick nerves to each globular part in ye surface of ye eye wch: he computes to be above 3000 in both eyes. with severall curious remarks on ye optick neves of knatts & other insects whose eyes are formed after the same manner' (JBO/10/67).

The letter and images are printed in:

A. Leeuwenhoek, ‘Concerning the eyes of beetles’, Phil. Trans. vol. 20, no. 240 (May 1698), pp. 169-75.

A. van Leeuwenhoek, Sevende vervolg der brieven (Delft: H. van Krooneveld, 1702), pp. 43-52.

A. à Leeuwenhoek, Epistolae ad Societatem Regiam Anglicam (Leiden: J. A. Langerak, 1719), pp. 38-47.

Related Fellows

Antoni van Leeuwenhoek (1632-1723, Dutch), Naturalist

Associated place

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