https://creativecommons.org/publicdomain/zero/1.0/https://www.rawpixel.com/image/14018169Edit ImageSaveSaveEditCropCustom TextSections of a furnace used in the refining of saltpetre. Etching by Bénard after L.J. Goussier.Original public domain image from Wellcome CollectionMorePublic DomainFree CC0 image for Personal and Business useInfoView CC0 LicenseJPEGSmall JPEG 765 x 1200 px | 300 dpiLarge JPEG 1250 x 1962 px | 300 dpiFree DownloadSections of a furnace used in the refining of saltpetre. Etching by Bénard after L.J. Goussier.More