31 .. 36 Gartsherrie 3 II 2 C 2 3 H 1H 1H 2 2 C 2 H 1H 2 C 2 1H 4 7.017 13,894,000 00003109 2043 107811 79.83 681 02117 7.210 71.97 676 1.01850 6.251 95.34 | 673 .02082 7.002 85.38 673 02100 7.066 89.82 671 .02102 6.813 81.94 664 .02089 6.936 75:01 658 .01810 6:052 61.98 657 .01857 6.102 00002785 1939 .07676 74.42 6-16 .01800 5.812 67.86 598 02239 6.694 4 ::::: 4 49 50 .. 53 3 5 Sumn = Mean 15, 242,320 (5) .00002886 (6) 2063 07850 (7) (2 ) 80.63 688 01971 (9) (10) (11) 6.774 (12) 26 29 41 46 (1) (3) (8) (4) 99 9 T = In which D, = the external, and do = the internal diameter, in inches. Do = the external, and do = the internal depth or vertical diameter in Elliptical sections. DB = the external, and d3 = the internal breadth or horizontal diameter in Elliptical sections. L = the length of the beam in feet. W = the load in lbs., tons, &c., dependent on the terms of Mt. M = Multiplier which varies with the Material, mode of fixing, loading, &c.: the value for rectangular and cylindrical beams is given by Tables 64,65, 66, and the Ratios in (359),(362). (335.) The value of My may be found from direct experiment by rule (327). Its most useful value is when W = the ultimate or breaking weight in the centre of a rectangular beam supported at both ends :-in that case it is simply the breaking load of a beam 1 inch square and 1 foot long. Table 64 gives in col. 7 the mean value of My for the breaking weight of 54 kinds of British cast iron at 2063 lbs., or 18.4 cwts., or .92 ton, and of course W will come out in lbs., cwt., or tons according to the Multiplier used :-col. 10 gives Mfor the safe dead load, which is taken at žrd of the breaking weight. This Table is based on Fairbairn and Hodgkinson's experiments. Table 65 gives the value of Mr for Timber, and Table 66 a reduced and condensed general summary. Table 67 gives the Transverse strength in connection with the Stiffness for the Safe working load as well as for the breaking weight: the ratio which these should bear to one another, or the “Factor of Safety," varies with the nature of the material and the character of the Strain, &c. See (880), &c. (336.) The application of the rules and Tables may be illustrated by examples. Thus to find the breaking weight for a beam of English Oak, 12 inches deep, 6 inches wide, and 15 feet long ;--we may take My from col. 6 of Table 66 at .2272 ton; then the rule (324) becomes 122 x 6 x .2272 15 13:1 tons breaking weight in the centre. Again: to find the depth of a beam of Riga Fir 10 feet long, 3 inches wide, to carry the TABLE 65.-Of the TRANSVERSE STRENGTH of TIMBER, or the Value of Mt, being the central Breaking Weight of a Beam 1 inch square, 1 foot long between end bearings. Kind of Wood. Max. Min. Mean. Authority and Number of Experiments. lbs. :: 9 ::::: :::::::: : : : 9 99 99 :: lbs. tons. Acacia 747 .3334 P. W. Barlow. green 622 .2776 1 Ebbels. Alder ... 530 • 2366 1 Ash, common 682 665 675 • 3014 6 Barlow. 815 .3638 2 P. W. Barlow. 785 •3504 1 Tredgold. 810 .3616 1 American 517 • 2308 Nelson. 680 - 3054 Denison, Swamp 388 • 1732 Black 287 •1281 Beech, common 538 494 519 *2317 3 Barlow. 677 3022 1 Ebbels. American, White 460 • 2054 Denison. 573 • 2560 Nelson. • 2610 Denison. Birch, common .. 815 727 771 • 3442 2 P. W. Barlow. 518 2312 1 Ebbels. 616 • 2750 Nelson, 842 3760 Denison. 445 • 2000 Cedar, Lebanon 498 •2223 412 • 1840 1 Tredgold. Bermuda 465 .2760 Nelson. Guadaloupe 681 • 3040 American, White 255 •1140 Denison. Chestnut, green 450 • 2009 1 Ebbels. Spanish,dry 592 382 487 • 2176 2 Tredgold. Deal, Christiania 657 587 622 • 2780 2 P. W. Barlow. 686 •3060 1 Tredgold. 521 .2326 Barlow. Memel 692 • 3090 P. W. Barlow. 545 .2433 1 Tredgold. Elm, English 348 334 338 • 1500 3 Barlow. 510 • 2410 1 Ebbels. Table 65.—TRANSVERSE STRENGTH of TIMBER, &c.—continued. Kind of Wood. Max. Min. Mean. Authority and Number of Experiments. 99 12 dry Wet Spruce . 99 : : : : : : lbs. lbs. lls. tons. 480 .2110 1 Ebbels. 382 · 1705 27 Peake and Barrallier. 1951 37 480 350 390 • 1741 4 407 • 1817 9 Barlow. 465 • 2076 1 • 1473 13 Barlow. 50+ • 2250 3 Tredgold. 1 Moore. 565 .2.22 Devison. 568 368 475 • 2120 Barlow. 568 364 418 • 1866 19 Beaufoy. 904 423 663 •2959 6 P. W. Barlow. Moore. 1 517 .2412 1 Ebbels. 570 434 496 .2214 8 Buttou. 507 155 490 .2187 3 Barlow. 428 224 334 •1491 25 Beaufoy. 526 .2322 Moore. 506 • 2530 Nelson, Moore. 2058 3 Barlow. 519 -2317 Moore. 569 .2510 Nelson. 555 • 2480 Denison. 621 .2770 99 Nelson, live TABLE 65.- TRANSVERSE STRENGTH of TIMBER, &c.—continued. kind of Wood. Max. Min. Mean. Authority and Number of Experiments. tons, • 4455 4 P. W. Barlow. 3715 Barlow. .3696 Nelson. •3755 Moore. .3861 Denison. • 2480 Moore. • 2513 • 2000 3 Barlow. • 2900 Nelson. - 2680 Young. . 1920 Moore. . 1875 Denison. .2428 3 Barlow. • 2428 24 Beaufoy. •313+ 7 Peake and Barrallier. • 2710 Denison. .2108 6 Peake and Barrallier. . 1770 Moore. . 1640 Barlow. • 1900 Denison. · 1213 7 Peake and Barrallier. .2165 Nelson. • 1600 Young. •1728 Denison. • 2120 Moore. • 2004 • 2509 . 1603 Barlow. - 2040 Moore. • 2710 1 Ebbels, • 1467 1 .2510 1 • 2000 Moore. 1540 Denison. •2388 1 Ebbels. .3660 3 Barlow. • 2947 2 Peake and Barrallier. .2826 Nelson. *2924 Denison. . 1629 Tredgold. • 2174 Ebbels. 272 485 358 387 475 99 449 562 359 457 Memel Archangel Plane-tree .. Poplar, Lombardy Abele Spruce American Sycamore Teak 607 328 570 419 99 315 535 821 660 99 892 717 Willow 633 655 365 487 |