In the γ-radiolysis of H2S with added buta-1,3-diene, H atoms appear to react before they become thermalised. With added benzene, propene, and but-1-ene insufficient scavenging occurs to say with certainty whether a similar situation applies, but indications are that it may be so for propene, and but-1-ene. Investigation of the effect of but-1-ene on the sulphur yield, indicates a dose rate effect which is explained by a competition between ion-recombination and diffusion to the wall enhanced by convenction currents. Yields of G(H2)=G(S)= 0.5 unscavengable by buta-1,3-diene are indicated, and evidence is given that excited sulphur atoms (S*) and S+ ions are probable precursors of these yields. Nitric oxide appears to react with SH radicals in a chain process producing H2O, N2O and S. Electric fields do not affect the radiation yields until electron acceleration just before saturation occurs, causes increased decomposition. The ratio of sulphur scavengable in the presence of a field is ∼4 : 1, which is much lower than in the absence of a field (13:1). This is evidence for production of excited S atoms by field accelerated electrons.