When I first saw this image, my thought was: laundry. A shirt above a tub. The image below comes with the short ritual of “Les Antipodiens”, the 60th degree in the French 1780 collection of 81 degrees which were condensed to the French Rite. An “Antipodian” is someone who comes from New Zealand or Australia. The French text actually explains the image (Microsoft translation):
The dress hanging in a basin signifies purity and innocence.
Left of the dress it says: “probitas” (‘virtue’).
Bibliotheque Nationale de France, Fonds Maçonnique, FM4 (1047 J), digitally available.