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.
... John Wesley and John Newton put
it among the works that influenced them at their
conversion. General Gordon carried it with him
to the battlefield.
Few ...