| Administrative History | 'Non-resident' was a sub-class of membership, indicating that the individual lived outside a 20 mile radius of London. Those within this radius were classed as 'Resident'. Non-residents would generally pay a higher one-off joining fee than residents but unlike the latter, paid no annual subscriptions.
Daguerrotype technology had only been announced to the public as the first commercially viable photographic process in January 1839. In August of that year the process was explained and manuals were available. Warburton references 'violet coloured gas' in the letter, referring to iodine which is obtained from kelp and used in the daguerrotype process. |