8vo. Illustrated diagram on separate leaf of heavier stock laid in, illustration replicated on inside of front wrapper showing the tunneling process. Original printed wrappers (faint vertical crease, light toning). Provenance: Thomas J. Long (contemporary ownership signature on title-page dated 1880).

FIRST EDITION. In the 1880s, Dowd was a key engineer involved in the pioneering Hudson River Tunnel project, which aimed to create an underground rail connection between New York City and New Jersey beneath the Hudson River. Dowd employed innovative techniques such as the use of compressed air to stabilize the tunnel environment and the implementation of shield-driven tunneling methods to advance the excavation. The project came to a halt on the morning on 21 July 1880 when a blow-out occurred causing air to escape along the side of the shaft which eroded away the Earth and wedged the inner lock door that could not be opened to allow the workers to escape and 20 drowned. The project was eventually completed as the North River Tunnels in 1908 and officially opened in 1910. RARE: we could only locate less than a dozen copies in institutions and no copies at auction.