Auction 333-341 Nigeria, Cameroon, Sudan & Worldwide Postal History - Day 4

Niger Coast Protectorate 1896: Registration Envelope, 2 d. handpainted unadopted essay in grey-green, blue and Chinese white, on thin brown tracing paper, dated "Sep. 2. 96." in pencil, central vertical crease, although retains much eye appeal. Rare.
Reference: The Postal Services of The British Nigeria Region, by Jack Ince & John Sacher, illustrated plate XII; The Postal Stationery of Nigeria, by Peter Horlyck, illustrated on pg. 51.