A photoelectric spectrum scanner has been used to measure absolute spectral energy distributions of a number of quasi-stellar radio sources. Most of the observations have been made between x 3300 and x 6000, but for 3C 286 and CTA 102 observations extend to nearby x 9000. In these, the infrared measures indicate the presence of the [0 iii] lines X 4959 and X 5007, and HP or H , and confirm previously published redshifts. It is probable that 1 + z = 2.40 for 3C 446. The C iii] line X 1909 is not detected in 3C 9. When the whole visual continuous spectrum of 3C 9 is taken into account, there is no evidence for a drop in the continuum below Ly-a, so that the estimate of the amount of neutral hydrogen in intergalactic space made by Gunn and Peterson is only an upper limit. The spectral energy distributions of CTA 102, 3C 245, and 3C 446 show two very distinct and in two cases radically different slopes (see Fig. 7). Absence of a detectable Balmer jump in 3C 48 and CTA 102 indicates that at the longer wavelengths the continuous spectrum is non-thermal in character and may possibly be synchrotron radiation; this is probably also the case in 3C 245 and 3C 446. The continuous spectrum of 3C 9 can be fitted either by a thermal bound-free plus free-free hydrogen spectrum or by a synchrotron model. The strength of Ly-a suggests that most of the continuum is not produced by a hot hydrogen gas. The flat portions of the spectra of 3C 273, CTA 102, 3C 446, as well as the whole observed spectrum of 3C 286, could be produced either by the synchrotron mechanism or by a hot hydrogen nebula; the present observations do not allow a choice to be made. From the strength of HP in 3C 48 it is found that a Balmer jump in emission of 0.3 mag. should occur if Te = 16000 K. The observations do not show such a jump and suggest a higher electron temperature. A comparison of the strengths of Ly-a and X 1550 of C iv in 3C 9 gives T = 20000 K, provided a significant fraction of all carbon atoms are in the form of C+++ and the carbon abundance relative to hydrogen is not very different from that in the Sun.