The note in the Forum ‘The Accuracy of Astronomical Observations at Sea’ by G. A. Harding (this Journal, Vol. VII, p. 195) and the paper ‘The Barcoo Observations’ by J. B. Parker and D. H. Sadler (this Journal, Vol. VII, p. 317) were interesting, but although some practical navigators have dabbled with the theory of errors one is apt to feel a little bit blinded by the science of the mathematicians on the subject of ‘errors’, when such things as ‘constant bias’, ‘quasi systematic error’, ‘internal standard deviations’, and a ‘ square root law’ (p. 320, Table I, Col. 7) are bandied about. One hopes one knows what they mean, but there is a lurking doubt, though one might not admit it, and they do not quite seem to click with the sort of phrases taught to navigators.