A diagram showing the two types of velocity dispersion we consider in this paper. The left panel is our explanation for the observed velocity dispersion in [Fe XXI] – a turbulent cascade in the hot, volume-filling intracluster medium (see Sect. 7.3). The right panel is our explanation for the observed velocity dispersion in the other lines we discuss in this paper. These other lines all have about the same value of σ_r ≈ 130 km s⁻¹ even though they are emitted from gas at characteristic temperatures ranging from below 10³ K up to several times 10⁵ K, we interpret the velocity dispersion we measure for these lines as the result of random motions from clumps which are magnetically confined inside the filament. We also note that Lyα is broadened additionally by the large optical depth that Lyα photons experience as they escape from the boundary layers around these clumps.