Paper, 'On the refraction of plane polarised light at the surface of a uniaxal crystal. II' by RT [Richard Tetley] Glazebrook Glazebrook writes: 'I have just discovered a source of error which had hitherto escaped my notice, and which seriously affects all the results I have arrived at. I have been using a spectrometer made many years since by Grubb, of Dublin, for the late Dr Robinson, of Armagh, and kindly lent to me by Professor Stokes. A chance observation has showed me that the object-glasses of both collimator and telescope in this instrument are strongly doubly refracting.' Glazebrook's earlier work on the refraction of plane polarised light at the surface of a uniaxal crystal can be found in volume 173 of the Philosophical Transactions of the Royal Society. Annotations in pencil and ink. Subject: Crystallography Received 4 December 1882. Read 14 December 1882. A version of this paper was published in volume 34 of the Proceedings of the Royal Society as 'On the refraction of plane polarised light at the surface of a uniaxal crystal. II'. 1882