Tamping, 32 Thickness of Lining Masonry, 78, 83 Thomson Excavating Machine, 22 Timber Lining, 72 Timbering (see Strutting). Tremies, 299 Trussed Centers, 70 Tunnel or Open Cut, 1 Tunnels: Baltimore Belt Line, 160 Classification of, 42 Fort George, 135 Murray Hill, 123 Simplon, 103 St. Gothard, 132 Hard Rock, 84 Drift Method, 102 Comparison of Methods, 141 Heading and Bench Method, 152 Heading Method, 130 Soft Ground: American Method, 172 Austrian Method, 176 Belgian Method, 144 English Method, 166 German Method, 155 Italian Method, 182 Pilot Method, 192 Quicksand Method, 188 Submarine: Detroit River Tunnel, 296 Harlem River Tunnel, 285 Hudson River Tunnel of Pennsylvania Railroad, 269 Milwaukee Tunnel, 226 Seine River Tunnel, 293 Severn Tunnel, 221 Van Buren Street Tunnel, Chicago, 282 Under City Streets: General Description, 201 Boston Subway, 203 Turbines, 86 Vacuum Method of Ventilation, 328 Value, Beverley R., 10 Van Buren Street Tunnel, 282 Ventilation, 325 Artificial, 327 Compressed Air, 330 Natural, 326 Plenum Method, 329 Quantity of Air, 331 Saccardo’s System, 330 Simplon Tunnel, 120 Vacuum Method, 328 Vernon-Harcourt, L. F., 221 Working Platforms, 286 Wyman, Erastus, 293 Transcriber’s Notes Inconsistencies in spelling and hyphenation have been retained except as mentioned below; non-English words and phrases have not been corrected except as listed below. The (minor) differences between the Table of Contents and the chapter headings have not been rectified. Page 36/132: Figs. 14 and 61 are identical. Page 92/93, Sommeilier: possibly an error for Sommeiller. Page 134, Soummelier: possibly an error for Sommeiller. Page 174, Footnote 11: presumably Fig. 92, indicating the planes of the sections, is from the same publication. Page 176, Austrian method: Dresden and Leipsic, and the Oberau Tunnel, are (and were in 1837) in Saxony, Germany (or Prussia). Page 179, The short transverse beam _c_, Fig. 90: there is no short transverse beam visible in Fig. 90, nor is it clear which other figure might be intended; there is therefore no hyperlink to the illustration. Page 279, Stirtling boiler: possibly an error for Stirling boiler. Pages 337 and 342, Arlberg: possibly an error for Aarlberg. Page 340, Wartha: possibly an error for Martha; Mertin: possibly an error for Merten. Changes made Footnotes, tables and illustrations have been moved out of text paragraphs; some table data have been re-arranged for better legibility. In some of the formulas brackets have been added for clarity. Several obvious minor typographical and punctuation errors have been corrected silently. Page 12, footnote 3: Chapter IX. changed to Chapter X.