The authors would like to thank Professor Bair for his insightful comments on ultrahigh-pressure viscosities. The viscosity model used by Schmidt et al.(1) was a Tait-like(2,3) model that has been shown to correlate accurately the viscosity of many fluids in the original investigations pressure range (0.1-275.8 MPa (40000 psi)) of interest. The upper pressure is indicative of the high pressures found in the petroleum industry(4). However, after discussions with Professor Bair, it became clear a reference model that can accurately model the viscosity of squalane at ultrahigh-pressures is of interest to those working in the area of tribology.