https://creativecommons.org/publicdomain/zero/1.0/https://www.rawpixel.com/image/14020421Edit ImageSaveSaveEditCropCustom TextMachinery used in the comparative testing of gold. Engraving by Mutlow.Original public domain image from Wellcome CollectionMorePublic DomainFree CC0 image for Personal and Business useInfoView CC0 LicenseJPEGSmall JPEG 1200 x 737 px | 300 dpiLarge JPEG 3424 x 2104 px | 300 dpiFree DownloadMachinery used in the comparative testing of gold. Engraving by Mutlow.More