Silica gel for col. Chr. (30-70 mesh) (1841) ...
Silica gel for col. Chr. (finer than 200 mesh) (1843) ...
Silica gel for col. Chr. (70-325 mesh) (1842) ...
Silica gel for col. Chr./ (70-230 mesh) (1844) ...
Silica gel for col. chr. (60-120mesh) (1845) ...