https://creativecommons.org/publicdomain/zero/1.0/https://www.rawpixel.com/image/14020114Edit ImageSaveSaveEditCropCustom TextCalipers for artillery measurement, with many formulae engraved on them. Engraving by A. Bell.Original public domain image from Wellcome CollectionMorePublic DomainFree CC0 image for Personal and Business useInfoView CC0 LicenseJPEGSmall JPEG 928 x 1200 px | 300 dpiLarge JPEG 2338 x 3023 px | 300 dpiFree DownloadCalipers for artillery measurement, with many formulae engraved on them. Engraving by A. Bell.More