Horiba Ltd., a Japanese manufacturer of infrared analysis devices, has acquired the French optical equipment manufacturer Instruments S.A. The acquisition complements Horiba's existing line of engine emission analyzers and medical analyzers. Instruments S.A. manufactures diffraction gratings, monochromators, wavelength division multiplexers and fluorescence systems. The two companies plan to develop optical emission products and sell Horiba analyzers through Instruments S.A.'s sales network outside Japan.