Copy letter from Joseph Larmor, to Mr [J W] Gifford Has some scruples about Gifford's paper ['The Refractive Indices of Water and of Sea-Water']. Dr [Tichard Tetley] Glazebrook thinks the discrepancy is due to error in Gifford's instrument [goniometer]. Thinks it would not cause much trouble to examine the circles of the instrument and find out which of them is false and in what manner and extent. 20 July 1906