THE GREAT TUNNELS OF THE WORLD by Charles W. Comstock.  Original 1908 offprint from the Proceedings of the Colorado Scientific Society, Vol. VIII (pp. 363–386), featuring “The Great Tunnels of the World” by Charles W. Comstock. Published in Denver by the Society in January 1908.  Read by Comstock at the Society's December 7, 1907 proceedings.  A substantial early‑20th‑century survey of major tunnel works worldwide, issued for engineers, geologists, and institutional members of the Colorado Scientific Society. These offprints were printed in limited numbers and are now scarce in commerce. Comstock’s paper is frequently cited in early civil‑engineering bibliographies and remains of interest to collectors of tunnel engineering, mining history, and Rocky Mountain scientific publications.  Ships carefully packaged with tracking via USPS Media Mail and Ebay International Shipping.