127. Shield Suggested by Greathead for the Proposed North and South Woolwich Subway 245 128. Beach’s Shield Used on Broadway Pneumatic Railway Tunnel 245 129. Shield for City and South London Railway 246 130. Shield for St. Clair River Tunnel 247 131. Shield for Blackwall Tunnel 248 132. Elliptical Shield for Clichy Sewer Tunnel, Paris 249 133. Semi-Elliptical Shield for Clichy Sewer Tunnel 250 134. Roof Shield for Boston Subway 251 135. Transversal and Longitudinal Section of Prelini’s Shield 252 136. Elevation and Section of Hydraulic Jack, East River Gas Tunnel 260 137. Cast-Iron Lining, St. Clair River Tunnel 262 138. General Elevations and Sections of Shields 270 139. Plan and Elevation of First Bulkhead Wall in South Tube, Manhattan 273 140. Typical Cross-Sections of One Tube of Pennsylvania Railroad Tunnel under the Hudson River 278 141. Sections of Cofferdam, Van Buren St. Tunnel, Chicago 283 142. Showing Working Platforms and Piles Sunk in Dredged Channel 286 143. Showing Sheeting-Piles for the Sides of the Caisson and Trussed Beam for the Roof 287 144. Showing the Caisson with the Working-Chamber 287 145. Showing the Tunnel Constructed within the Caisson 289 146. Showing Sides of the Caisson and Supports for the Roof 290 147. Showing the Roof of the Caisson Formed by the Upper Half of the Tunnel 291 148. Showing the Tunnel Completed by Building the Lower Half within the Caisson 292 149. Transversal Section of the Caissons for the Tunnel under the Seine River 294 150. Showing the Joining of the Caissons at the Pont Mirabeau Tunnel under the Seine River 295 151. Cross-Sections and Plans of the Detroit River Tunnel 298 152. Tunneling through Caved Material by Heading 306 153. Tunneling through Caved Material by Drifts 307 154 and 155. Filling in Roof Cavity Formed by Falling Material 307 156. Timbering to Prevent Landslides at Portal 308 157. Shortening Tunnel Crushed by Landslide at Portal 308 158. Extending Tunnel through Landslide at Portal 309 159 and 160. Relining Timber-Lined Tunnel 316