[Chimera-users] Increase/decrease the sphere

Dear Chimera users, Could anybody tell me whether there is a way in chimera to increase/decrease the size of the spheres/ball-and-stick in atom display (Action-->Atoms/Bonds-->sphere...). The wireframe has an option in "wire width", is there something like that for the above two options ?? Waiting for yours suggestions. Thanks in advance. Best, TKP