Abstract: Apparatus for the manipulating and testing of molecules and in particular of DNA comprising a surface on which the molecule is anchored on multiple points at one end and a paramagnetic bead on which said molecule is anchored on multiple points at its other end, magnetic means for applying a force to the bead, said magnetic means being used to control the stretching and rotation of said bead and molecule, optical magnification means and a camera for the visualisation of said bead, computer means to which the images of the camera are transmitted, said computer means comprising means for analyzing the motions of the bead. A method for the manipulating and testing of molecules and in particular of DNA in which a molecule is anchored at one end to a fixed surface and at its other end to a paramagnetic bead wherein said molecule is anchored on multiple points at each of said ends.