The Farnesian Hercules, plate one from Three Famous Antique Sculptures by Hendrick Goltzius https://www.rawpixel.com/image/8976893/photo-image-paper-cloud-cartoonFree Image from public domain licenseMathematicians and astronomers: twenty portraits. Engraving by J.W. Cook, 1825. https://www.rawpixel.com/image/13989355/mathematicians-and-astronomers-twenty-portraits-engraving-jw-cook-1825Free Image from public domain licenseJohn Napier, seated, wearing a skull cap, his right hand resting on an open book. Line engraving by R. Cooper. https://www.rawpixel.com/image/13996012/image-cartoon-face-handFree Image from public domain licensePhysics: a magnetic needle [], with logarithmic apparatus (below). Engraving. https://www.rawpixel.com/image/13991535/physics-magnetic-needle-with-logarithmic-apparatus-below-engravingFree Image from public domain license