London: Office of the Commissioners of Patents for Inventions, 1874. 12mo, pp (xxx), (72), (66, appendix). Original blue printed paper covers. Covers a bit darkened, with some spine chips, detached front wrapper neatly repaired internally with clear archival paper tape; small library rubber stamp at head of title page but no other library marks; else a VG copy. No illustrations in text. Note: lighter parcel, any default postage rate may be reduced.