Copy letter from an unknown correspondent, to Messrs B Donkin & Company, 55 Southwark Park Road, Bermondset, S.E. 'We find your name on the valve of our gasmeter. Would it follow from this that you made the meter too? If so, we shall ask you to examine it, as we have reason to think that it registers very much higher than it ought to'. 21 July 1891