The basic spectrometer has a light source S illuminating a slit that acts as an object for lens C. After refraction by the prism, the light is focussed by lens O on cross-hairs R. The earliest picture of a spectrometer I have found is this cut from Hauksbee and Whiston's Course of Lectures, ca. They take light, separate it by wavelength and create a spectrum which shows the relative intensity of these separate wavelengths. An optical spectrometer (spectrophotometer, spectrograph or spectroscope) is an instrument. This work presents a laboratory experiment which gives new purpose to old optical spectrometers while building knowledge and confidence of students in their understanding of chemical instrumentation. Students are given a guided tour of spectroscopic instruments, starting from the simplest, and are. The underlying principle involves accelerating positively or negatively charged ions of a sample material and then deflecting them with electrical or magnetic fields in order to determine mass and frequency of atoms.