A modulated crossed beam method is used to measure cross sections for electron impact excitation of atomic hydrogen to the lower excited atomic levels, n - 2, 3 and 4 from threshold electron impact energy up to 300eV. The objective is to provide a test of basic scattering calculations and to resolve existing discrepancies between theory and experiment. To this end, the measurements are calibrated on an absolute basis, and the angular dependencies are measured, the only measurements of this kind in the United States.
