TYMPAN COVERS AND SHEETS COMPRISING A CLOTH, PAPER OR OTHER SHEET MATERIAL TO WHICH IS BONDED ROUNDED OR SPHERICAL BODIES OR PROTUBERANCES, SAID SHEETS BEING USED (1) AS A PRINTING ACCESSORY, TO PREVENT OFF-SET, TO PREVENT THE BUILDING UP OF STATIC CHARGES OF ELECTRICITY, TO GIVE A HARD SURFACE TO PRINT AGAINST OR TO PERFORATE AGAINST, AND THE LIKE, (2) AS A COVER FOR IDLER ROLLS, (3) AS PADS FOR ABRASIVE BELT SANDING MACHINES, AS COVERS ON MACHINES FOR COATING SHEETS OR FILMS TO PREVENT STAT...