A spectroscope is a device which measures the spectrum of light. Early spectroscopes were simply a prism with graduations marking wavelengths. Modern spectroscopes generally use a diffraction grating, a movable slit and some kind of photodetector[?], all automated and controlled by a computer.
... Karenin. She is invited from her home in St Petersburg to Moscow to mediate the marital discord of her brother Stepan (Stiva) Oblonsky and his wife Darya (Dolly) ...