Unpublished paper, 'On black soap-films' by A W [Arnold William] Reinold and A W [Arthur William] Rücker The authors continue their research into soap films (see volume 26 of the Proceedings of the Royal Society, 'On the thickness of soap films'). They summarise their existing research and present further experimental observations. Annotations in pencil and ink throughout. Subject: Chemistry Received 1 March 1890. Read 27 March 1890. 1890