235. Gate roads resting on brattice wood and wax walls. 236. South Staffordshire thick-coal workings: plan 171 172 242. Longitudinal section of shafts (St. Etienne) 176 176 176 250. Great vein (Bristol Coal-field). 245. Mammoth vein: section of breast (Pennsylvania) 246. Mammoth vein: elevation (Pennsylvania) 248. Section of gate road in thin seam 249. Section through working places in four contiguous seams (Warwickshire Coal-field) 251. Yorkshire colliery: longwall face in steps 177 177 178 178 179 179 180 252. Section across level gates, showing longwall working place 263. Ffestiniog Slate-mine: section of working place 288. Air-currents in shallow pits, summer and winter 199 296. Pressure and temperature in furnace pit, dumb drift 205 300. Richards's indicator on cylinder and velocimeter 301. Richards's indicator diagrams. 213 214 336. West Riding Collieries: section of west chain road 269 337. Whitehaven Colliery 271 338. West Stanley Colliery: plan 272 339. Elemore Colliery: plan of road 274 344. Water-cart 343. Water-cart: revolving brush 345. Pipes and spray (Ynishir) 346, 347. Pipes, spray, and compressed air (Dowlais) 274 276 276 Water-cart: pump (Kirkhouse and Lewis) 276 277 277 278 357. Shielded lamp ("Protector," Mueseler): section 281 281 282 283 283 284 285 285 286 286 286 |