This paper presents measurements of specular and non-specular reflectivities of a W/Si multilayer with period d equals 135.1 angstroms. Angular dispersive measurements were performed at 8.05 keV and 59.3 keV, while energy dispersive measurements were made in the range of 17 keV to 130 keV. At an incidence angle of 1.57 mrad the fourth order Bragg- reflection is found at an energy of 125 keV with a reflectivity in excess of 50% and a bandwidth (FWHM) of 3%.