Title Massachusetts Institute of Technology wavelength tables : with intensities in arc, spark, or discharge tube of more than 100,000 spectrum lines most strongly emitted by the atomic elements under normal conditions of excitation between 10,000 A. and 2000 A., arranged in order of decreasing wavelengths / measured and compiled under the direction of George R. Harrison by staff members of the Spectroscopy Laboratory of the Massachusetts Institute of Technology ; assisted by the Works Progress Administration.