"Trio Of Big Mercury Balls..."
These are not recent balls, they are not balls of forgiveness ... It is a family of three old large Christmas balls in thick mercury glass. Of unknown origin but certainly from a region where Christmas was celebrated with pomp. A round ball with facets like a melon, followed by one in the shape of a star (from Bethlehem) ... and its younger sister. Today the balls are tinned because working the mercury as in past centuries was harmful and then the adhesion of the mercury on the glass is not perennial because of the coefficient of expansion of the two materials. PS the hen's egg serves as a visual abacus. 
Le Magazine de PROANTIC
TRÉSORS Magazine
Rivista Artiquariato