Copy letter from Herbert Rix, to Robert Warington, Fellow of the Royal Society Rix finds from Dr [Michael] Foster's Council minutes that the permission accorded Warington to use certain engravings in the Royal Society library for the purpose of obtaining photographic copies did not include any portrait which may be copyrighted. Rix learns from Cassell's 'Cyclopedia' that whereas copyright for a book endures for the lifetime of the author and seven years afterwards, or for a minimum of 40 years after publication, the term for an engraving is 28 years. 22 December 1890