Letter from Silvanus Phillips Thompson, University College, Bristol, to [William Fletcher] Barrett Sends his pamphlet and asks Barrett to 'put in a word' for Letts at Belfast. Notes on his and Barrett's researches, including on the trap-door hygrometer and on improvements to Edison's loudspeaker. Suggests an experiment to Barrett [annotated by Barrett: 'a very valuable suggestion and led to my forming a chalk cylinder battery']. Relates how he and Lodge have been working on the induction balance independently. Laments the loss of [James Clerk] Maxwell. 7 November 1879