The gaseous component of the reflection nebula surrounding HD 26676 is investigated by comparing the UV spectrum of the star with that of the foreground star HD 26793. The physical properties of the cloud are constrained under the assumption of Mg photoionization and H ionization by cosmic rays and taking into account the effect of the stellar radiation field on the Mg(0) ionization rate. The average ionization rate is obtained as a function of the extension of the nebula along the line of sight to the embedded star (R). The values determined for the temperature, the mean density, and R for a cosmic ray ionization rate of about 10 to the -16th/s are found to be typical of diffuse H-I regions.