Differential Stroemgren uvby photometric observations from the Four College Automated Photoelectric Telescope of four magnetic Chemically Peculiar stars are presented. We refined the period of 63 And to 4.1890 days. The period of the sharp-lined Si star HD 192913 is 16.840 days, a value close to, but slightly different from published values. HR 8240, a sharp-lined Si star, is found not to be a photometric variable. Comparison of four color photometry of 108 Aqr by Morrison and Wolff and from the Four College APT indicates that subtle changes in the shapes of the light curves, especially that for u, have occurred suggesting that this star may be precessing.