Letter from Charles Thomson Rees Wilson, Glencorse, Storey's Way, Cambridge, to 'Dear Crowther' Sends a copy of his description of a capillary electrometer from the Royal Society Proceedings of 1916. His promise to write a more detailed account has not been kept. The instrument used for later observations is described in Philosophical Transactions. Gives a description of his horizontal tube electrometer with a sketch. 1 October 1925