33
TABLE OF THE STRENGTH OF MATERIALS. *
COMPRESSION.
Material.
Weightof a cubicfoot in
ounces.
lbs. avoirdupoisrequired tocrush a cubicquarter of aninch.
Modulus of frac-ture or height ofa column onequarter of aninchsquare in sectionof the material,equal in weightto the crushingweight.
Feet.
Cast iron taken from the"'
- , .
block -
7033
9773.5
51229
Ditto (horizontal casting)
u § 3
g cd«’E
7113
10114
52422
Ditto (vertical ditto)
Wgoft
7074
11136.75f
58040
Cast copper crumbled with
8788
7318
30698
Fine yellow brass
8396
10304
45246
Wrought copper
-
8879
6440
26737
Cast tin
-
7291
966
4884
Cast lead
11352
483
1568
lbs. avoirdupois
of a column
to crush a cubic
inch square.
inch.
Elm
500
1200
5530
Fir -
-
600
2000
7680
English oak
-
845
4000
10906
* See Experiments, by George Rennie, Jun. Esq., Part I. Phil. Trans.1818. The table, page 24, Tract III. was printed before the author hadseen this paper. See Barlow’s Essay, Strength and Stress of Timber.
f Mr. Reynolds deduced that 448000 lbs. avoirdupois, or 200 tons, wererequired to crush a cubic quarter of an inch of iron, cast at the furnace°f Maidley Wood, of the quality called gun-metal; whereas these ex-periments show that five tons only are required, and one of them was upongun-metal. The strength of the cast iron bridge of 600 feet span, pro-jected by Messrs. Telford and Douglas, for London Bridge , was derivedfrom Mr. Reynolds’ experiment; and so late as 22d April, 1811, it wasconsidered accurate. Probably all iron bridges constructed before Mr.G. Rennie’s experiment in 1818, are founded upon data erroneous inrespect to the strength of cast iron, in the ratio of 200 to 5. See Appen.13 Lond. Port. sel. com. 1801, and Mr. Telford’s Rep. to Lords of Trea-sury, 22d April, 1811. App. Rep. Holyhead Roads, page 28.
See Lecture 13th, Course of Lee. on Nat. Phil. Vol. I.; and Table,vol. II. page 509. Dr. Thomas Young , M.D.