https://creativecommons.org/publicdomain/zero/1.0/https://www.rawpixel.com/image/13961829Edit ImageSaveSaveEditCropCustom TextOptics: optical phenomena. Coloured engraving by J. Emslie, 1850, after himself.Original public domain image from Wellcome CollectionMorePublic DomainFree CC0 image for Personal and Business useInfoView CC0 LicenseJPEGSmall JPEG 956 x 1200 px | 300 dpiLarge JPEG 1606 x 2016 px | 300 dpiFree DownloadOptics: optical phenomena. Coloured engraving by J. Emslie, 1850, after himself.More