Masonry maintenance, 424

Masonry piers, 167

Masonry, stone, repairs to, 420

Materials and supplies, 384

available, 484

best proportions of,

for concrete, 387-389

checking of, 380

counterweights, 294

employed in military bridging, 474

purchasing cheaply, 386

quick ordering of, 385

special, for contracts, 373

stock, 372

storage of, 382, 386

unloading of, 380, 381

versus labor, 18

versus time, 18

Mathematics in bridge-economics

investigations, 175

Mattress work, 122

woven brush, 474

Mayarí steel, 33, 34

cables, 279

Medium spans, erection of, 399

Members in military bridges,

sizes of, 477

Men,

management of, 368, 369

treatment of, 385

Mental effort, economics of, 18

as applied to inspection, 364

Merriman and Jacoby's treatment of

cantilever bridges, 261

Metal,

cleaning of, 422, 445

for shop coat, 441

life of, 430

marking of, 374

minimum thickness of, 201

protection, economics of, 430-448

storage of, 376, 441

straightening of, 374

structural, prices of, 23

trimming and cutting of, 374

"Metalcote," 432

Methods,

comparison, 14

contract-letting, 339, 340

erection, 123

profit-sharing contract, 345, 346

Military bridges,

bolts, 477

classes of, 463

concrete, 476

deck or flooring, 474

economics of, 459-485

improvisation in, 478, 479

inspection, 485

joints and fastenings, 476

labor, 478

lack of strength, 459

Military bridges,

loading, 481

paint, 476

piling, 475

plant and tools, 464, 477

standardization, 478, 479

steel, 475

stone, 476

timber, 475

transportation of materials, 482

types, 464

typical, 465

waste not justified, 462

Mill inspection, 363

Milling and planing, 377

Minimum thickness of metal, 201

Mississippi River Bridge, economic

study for replacement of, 13

Mississippi River bridge or tunnel

at or near New Orleans, 296, 319

Missouri River Bridges,

East Omaha, 131

Fort Leavenworth, repairs to, 408

Sioux City, 131

Missouri Valley Bridge Company, 439

Mixed carbon and alloy-steel bridges, 30

Mixing concrete,

economics of, 386

increasing fluidity of mixture, 391

manner and time of, 391

water, amount of, 392

Moisture changes, provocative of

cracks in concrete, 456

Molybdenum,

as an alloy, 34

economic benefit from, in steels, 44

gain involved by increasing

percentage of, 49

Molybdenum steel, 36

bridges, use in, 487

Commercial Steels (catalogue), 36

economic comparisons of, 44-51

tests of, 38-43

Monthly estimates to be made

promptly, 381

Montreal enterprise, 7

Motive power dependent on location

of structure, 310

Movable bridges,

comparative costs of various

types of, 297

economics of, 284-309

effect of wind pressure on, 293

examples illustrating use of economic

curves for, 304-308

main elements in, 314

pavements for, 293

quickness of operation in, 293

skew layouts for, 303

Multi-cylinder gasoline engine, 313

Multiple punches, 375

effect of, 206