Abstract: A precious stone setting, especially for diamonds, is achieved without adversely affecting the value of the stones, and in an essentially invisible way, by forming slight notches at the angles of the culet in such a way that the depth of the notches is small and the distance separating the bottom of two opposite notches is very much greater than the width of the table of the stone. A metal matrix is used to hold the stone, the metal penetrating into the notches.

Abstract: An inclination signaling device with respect to the horizontal, namely associated with a racquet for a tennis game, comprising an enclosure having at least two juxtaposed planes forming a dihedral on which a ball contained in said enclosure can move, the first plane of the dihedral being arranged along the axis of the handle and perpendicularly to the plane of the stringed surface of the racquet, the second plane of the dihedral forming a maximum angle of 90.degree. with said axis and said first plane, and comprising an electrical contact at its end opposite the line of junction of the first and of the second plane, said electrical contact being connected to a signaling device, whereby said ball is projected onto said electrical contact under the effect of the centrifugal force in the course of play by rolling over said second plane of the dihedral and provides a signal if the axis of the racquet is dipped downwards.