This is a photocopy of the Prospectus in the Library of the Sir John Soane's Museum (ref. no. 2433). Haughton was, from 1803, resident engraver and printer to Henry Fuseli.
Provenance
The original from which this photocopy was taken was originally folded and sealed as a letter, verso of blank leaf inscribed in ink John Soan Esqr. / Lincoln Inn Square.
With handwritten inscription at the foot of p. [4], 'photocopy from: Soane Museum Library (ref: Private Corresp. XVI G.16)'.