I came across this excellent website, the Wellcome Collection. It is a free museum and library in London which creates “opportunities for people to think deeply about the connections between science, medicine, life and art.” Among other fascinating content, I found some beautiful — and free! — public domain images in their digitized collections. Below are some examples.
watercolour, 1883 — modified t.g.
line engraving by W. Wellstood, 1856,
after J. B. Wandesforde — cropped t.g.
paper work with letterpress, 1800s.
after C. Sharp, 1700s — modified t.g.
Lithograph, 1800s — modified t.g.
M. Moreau, 1806–1809
cut flower. Watercolour — modified t.g.
wearing spectacles and an eyeshade. Wood engraving
after A. Oberländer — modified t.g.
