ON the Presence of [Fe x] and [Fe XIV] Emission in NGC 4151

Observations at 28 A covering the spectral regions where [Fe xiv] X5303 and [Fe x] X6374 emission should be found in the Seyfert galaxy NGC 4151 do not confirm the presence of [Fe xiv] X5303. This result, together with the intensity measured for [Fe xi X6374, indicates that photoionization rather than collisional ionization produces the [Fe x] emission. The observations agree quantitatively with predictions by Osterbrock based on a photoinnization model by Williams and Weymann for NGC 4151.