The horizontal dispersion of relatively large daytime TID events seen by the Dartmouth rapid-run ionosonde network is found to conform, at least qualitatively, to that predicted by previous theoretical treatments of freely propagating gravity waves in the presence of dissipation. The availability of TID vertical trace speeds, in addition to horizontal speeds, has allowed a direct comparison with gravity wave dispersion relations, and dissipative criteria. Good agreement is found with theory for waves measured at the height of maximum gravity wave amplitude, but rather less convincing results are found at greater heights. The latter may be explained in part by the fact that ion diffusion was neglected in the inversion technique employed to derive the vertical component of the phase propagation vector of the gravity wave from that of the TID.