A recent paper, (Jones and Wyatt, 1970) reports that the catheter tip electromagnetic velocity probe described by Bond and Barefoot (1967) and Warbasse, Hellman, Gillilan, Hawley, and Babitt (1969) is thermally unsafe. We have evaluated the true power dissipation of this probe and have found it to be comparable with the dissipation of the catheter tip probe described by Mills (1966) and Mills and Shillingford (1967), and evaluated thermally by Jones and Wyatt (1970). The temperature rise of a probe is directly related to the power dissipation of the probe. Any statement regarding the thermal safety of the Mills probe applies equally to that of Bond and Barefoot. We conclude that both probes are thermally safe, except possibly for long periods of operation under zero flow conditions.