https://creativecommons.org/publicdomain/zero/1.0/https://www.rawpixel.com/image/13955491Edit ImageSaveSaveEditCropCustom TextBuildings and plant for producing saltpetre. Watercolour by A. Kroll, 1806.Original public domain image from Wellcome CollectionMorePublic DomainFree CC0 image for Personal and Business useInfoView CC0 LicenseJPEGSmall JPEG 1200 x 996 px | 300 dpiLarge JPEG 3500 x 2906 px | 300 dpiBest Quality JPEG 7239 x 6011 px | 300 dpiFree DownloadBuildings and plant for producing saltpetre. Watercolour by A. Kroll, 1806.More