Public domain
Portrait of A.C. Oudemans Jr., Professor of Chemistry at the Polytechnic School Delft
From the collection of Rijksmuseum, Amsterdam. Free to download, adapt and use — no permission needed.
Credit linePortret van A.C. Oudemans Jr., hoogleraar scheikunde aan de Polytechnische School Delft. c. 1886 - in or before 18. anonymous. Rijksmuseum, Amsterdam. Public domain.