I wish to thank Dr. Clemence for pointing out1 the flaw in the interpretation drawn in my paper that the error in observed altitude due to tilt of the sextant is a maximum when the altitudes are in the neighbourhood of 45°. The purpose of a correction table is either to supply the correction or to indicate the most favourable or unfavourable circumstances. I agree that my table does not fulfil this purpose; the argument β is unknown. Moreover the table gives corrections for all combinations of altitude and β this is incorrect, as some values of β are impossible for some altitudes, and a square form of table is therefore not permissible.