Pocketbook of Useful Formulæ and Memoranda
for Civil and Mechanical Engineers

18 MOLESWORTH'»» POCKKT-BOOK Strength and Weight of Materials—continued. Timber—eontinu&l. Specific Gravity. Weight of a cubic foot. 2.2 Tensile Strength per aq. in. Crushing Strain per aq. in. h • 1 lbs. lbs. lbs. | lbs. 11«. Elm, English ., .. •553 34 *02 13,200 10,300 782 ■579 36 *021 14,000 — 1100 Canadian •725 45 •026 — 1 — 1920 Fir, spruce .. .. •512 32 •018 10,100 6,5001490 Hornbeam .. .. •76 47 •027 20,000 4,600 — , Ironwood .. .. 1-15 71 •041 — — 30Qfl Jackwood .. .. •67 42 •024 —- —— 183( Larch •543 34 •019 8,9001 3,200 133C 5,5<0 1660 •556 35 •02 10,200 , Lignum vitæ .. .. 1-333 83 •048 11,800 10,000 3440 Lime .. •564 35 •02 — Mahogany, Nassau •668 42 •024 1719 „ Honduras •560 35 •02 21,ÜÜ0 8,000 1910 _ Spanish •852 53 :o3i 8,200 1300 Maple ,. ... •675 42 •025 10,600 —• 1694 Oak, African .. .. •988 62 •035 2523 „ American, red •85 53 •03 10,000 6,000 16«<J „ ,, white •779 49 •028 — —— 1600 „ Englibh .. .. •777 48 •028 10,000 6,400 •934 5» •034 19,000 10,600 1690 Pine, red .. .. •576 36 •021 12,000 5,400 1200 •657 41 •024 14,000 7,500 1530 „ white .. .. •432 27 •015 —— 1229 •553 34 •02 —— — —— „ yellow .. .. •508 32 •018 5,300 1185 „ Dantzic .. .. •649 40 •023 «,000 5,400 1426 „ Memel .. .. ■550 34 •02 — 1348 •601 37 •021 — •— —— „ Elga .. .. •466 29 •017 —— —— — •654 41 , -023 14,000 — 1383 Satinwood .. .. •96 60 . -034 I - — 3200 1 Teak •74 46 •026 8,000 12,000 2110 •86 54 I *031 ;15,000 — Note.—The transverse strength is the coefficient K in the formula for strength of rectangular beams, but in lbs. The modulus of rupture may be found by multiplying the transverse strength by 6.