The design of a new ion spectrograph is described. Using magnetic deflection, analysis can be made of the velocity spectrum of the ions. For a given entrance angle to the magnetic field the foci lie on a straight line and second order focusing can be obtained. Application of an electric field parallel to the magnetic field causes displacement of the focal line to an extent determined by the charge‐to‐mass ratio of the ion. The image on the focal plane is thus a set of lines one for each ion species, the velocity distribution being displayed along each line.