A magnetic lens spectrometer has been built and tested. New features include (a) alignment with the earth's magnetic field to eliminate the deflection of the focal spot by this field, (b) use of a segmented coil to achieve a substantial reduction in spherical aberration, and (c) use of cathode rays for alignment, calibration, and for measurement of the aberration. Completely automatic operation has been achieved. Special attention is given to the effects of source backing and to focusing conditions for electrons in the very low energy region.