The cathode-ray beams of electrostatically focused cathode-ray tubes were studied by mass spectrographic methods. The negative-ion components focused on the fluorescent screens were made evident by their ability to change the fluorescent qualities of the screen material. Persistent appearance of m/e values of 16, 26, 35, and 37 in the tubes studied were due to oxygen, some organic molecule, as C2H2or CN, and chlorine, respectively. Many other components were found in tubes with various preparation histories. Direct evidence of negatively charged molecules of the cathode material were found which may be of some aid in the theory of sputtering. An explanation of screen discolorations appearing under different conditions of bombardment and life is given in terms of the effects of negative ions, positive ions, and electrons of different energy. The presence on the bombarded screen of a latent image which may be rendered visible by chemical means is discussed.