Bill, A. [Augustus] Stroh, telegraph instrument maker, 34 Brook Street, Euston Road, London, to the Royal Society 'Expenses for exhibiting Professor [Charles] Wheatstone's telegraph instruments at the soiree' [the Royal Society's conversazione]. The bill is for £2.2s.0d. in total, signed as received by Thomas Lehmann for A. Stroh. The engraved bill-head features Stroh's address details. 17 May 1861