452 



INDEX 



Liquids Continued 

 mechanics of, 68-85 

 pressure, 69-70 

 properties of, 68 

 use in industry, 68 

 Lubricants, 

 greases, 152 

 object of, 152 

 oils, 152 



requirements of good, 154 

 solid, 153 

 Lumber, 396-411 



cause of rottenness in, 415 

 classification of sources of, 404- 



410 



cutting boards, 400 

 cutting planks, 400 

 defects of, 412-416 



case hardening, 414 



checks, 414 



knots, 412 



warping, 414 

 effect of seasoning on strength, 



416 



felling timber, 398 

 figure, 399 



forest trees make good, 396 

 grain, 399 



methods of sawing, 399 

 seasoning of, 400-404 



kiln-drying, 402-404 



natural method, 401 

 shade trees, make poor, 396 

 source of commercial, 397 

 two types of trees, 396 



M 



Machines, 

 and tools, 22 

 centrifugal, 60 

 mechanical principles of, 22- 



25 

 power, 



measurement of, 47 

 wood-working, 432-438 (See 

 also "Wood-working ma- 

 chines") 

 why used, 22 

 Magnetic field, 190 

 Magnetism, 



and electricity, 167-183 



magnetic field, 167 



nature of, 167 

 Magnets, shape of, 167 

 Mahogany, 394 

 Malleability, 4 



table of, 5 



Manufactured gas, 118 

 Maple, 393, 405 

 Mariner's compass, 168 

 Mass, 10 

 Materials, 



strength of, 233-248 (See also 



"Strength of materials") 

 Matter, 



indestructibility of, 5 



properties of, 1-6 



three states of, 86 

 Measure, 7-21 



coiled belting, 287 



electrical units of, 172 



of distance, 8 



of electric power, 173 



of screw thread, 253 



of stresses, 237 



precision of, 17 



table of, 12 



units of, 7 

 Mechanical advantage, 26 



cost of, 49 



Mechanical drawing supplies, 225- 

 232 



blue-print paper, 231 



drawing paper, 227 



erasers, 228 



India ink, 231 



lead pencils, 225-227 



perspective drawing, 230 



required, 225 



tracing cloth, 230, 231 



working drawing, 229 

 Mechanical principles, 24 



of machines, 22-25 

 Mechanics of liquids, (58-85 

 Mercerizing, 164 

 Metals, weight per cu. in., 241 

 Metric system, 13-16 

 Mixtures, chemical, 126 

 Molding machine, 435 

 Molds, 439-446 

 Molecular weight, 130 

 Moment of forces, 27 

 Momentum, 55 



