SEVERAL investigators using a variety of optical instruments have indicated that small components of the ionized matter in H II regions are in a highly turbulent state1–5. In particular, Shcheglov3, using a photographic, single etalon Fabry–Perot at Hα in a non-classical combination with a telescope, found small components with turbulence of up to 100 km s−1 in M17 (NGC 6618), M8 (NGC 6523), the Orion nebula (NGC 1976) and M16 (NGC 6611). With this instrument he effectively took photographs at three adjacent positions in wavelength through a tunable 0.7 A filter of the whole of these nebulae. They changed shape at different wavelengths though this was only apparent with widely varying exposure times.