
Historical introduction.- Elementary description of spectrometers.- Analogy with geometrical optics.- Electron motion in cylindrical fields.- Semi-circular spectrometers.- ?2 Spectrometer.- ?10 Spectrometer.- (?/2)?13 Spectrometer.- Prismatic (sector) spectrometers.- Correctors and non-symmetric fields.- Toroidal ("orange") spectrometers.- Trochoidal spectrometers.- Lenses.- Short lenses.- Intermediate lenses.- Optical analogy spectrometer.