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.
... and international statesman
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Francisco de Orellana - first to navigate down the Amazon River
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William Parry[?], (born 1790), Arctic explorer
Robert Edwin Peary, ...