on the Strength of Materials. 173 
Weight of the dist. of bearings. Ibs. 
138 (Bar of 1 inch square, bars, lbs. oz. ft. avoir. 
through the diagonal .. 2 8 2 8 851 
139 (Half the above bar ‘4 att 1 4 1587 
Dit 3 rj 
140 (Bar ee deep.by inch : 9 5 28 2185 
141 Half the above bar .. s i 4 4508 
142 f Bar 3 in. deep, by 4 inch thick 9 15 2.8 3588 
143 | Half the bar .. “4 we 1 4 6854 
144 Bar 4 inches, by +} inch thick 9 7 2 8 3979 
145 Equilateral triangles with the angle up and down. 
146 ( Edge or angle up a 9nd 2: JS 1437 
147 angle down .. 9 7 2 8 840 
148 ) Half the first bar ite ats 1 ‘4 3059 
149 Half the second bar .. a 1 4 1656 
150 A feather-edged or , bar was cast whose dimensions were 
151 ie inches deep by 2 wide 10 O edgeup2 8 3105 
152 @ Half of ditto 
N.B. All these bars contained the same area, though dif- 
ferently distributed as to their forms. 
ments on curved bars the deflexion is given, but the thickness of the bars 
is not stated. It is true Rondelet has made some experiments en cast-iron 
where the successive deflexions were registered, but these experiments are 
not very regular; besides, it would be desirable to have experiments on 
British iron. 
As I have two experiments by me, I shall take this opportunity of laying 
them before your readers. A bar of cast-iron, from a Welsh foundry, 
which did not yield easily to the file, was laid upon supports exactly three 
feet apart; the bar was an inch square, and when 308 Ibs, were put into a 
scale suspended from the middle of its length the deflexion was found to 
be $-16ths of an inch; whence the height of the modulus of elasticity is 
6,386,688 feet. The experiment was made by Mr. R. Ebbe!s, at Garnons, 
near Hereford. A joist of cast-iron 9 inches deep, resembling in form the 
letter I, was laid upon supports 19 feet apart, first on its edge, when the 
deflexion from its own weight was 3-40ths of an inch.. It was then laid 
flatwise, aud thed« flexion from its own weight was 24 inches. The castings 
were from Messrs. Dowson’s foundry, Edgware-road. The iron yielded 
easily to the file. The height of the modulus of elasticity according to the 
€xperiment on the joist flatwise is 5,100,000 feet 
—— on the edge is 5,700,000 —-. 
The deflexion being very small when the joist was on its edge, perhaps it 
was not measured with the necessary degree of accuracy, as a very sinall 
error would cause the difference in the result. The following tablet con- 
tains the value of the modulus for cast-iron, according to the experiments 
above stated. Height of Modulus in feet. Experimentalists, 
Cast-iron (Welsh) ; 6,386,688 Ebbels. 
Cast-irun : J 3,500,000 Banks. 
Cast-iron, gray French, . 5,095,480 Rondelet*. 
Cast-iron, softdo. . : 4,247,000 Rondelet*. 
Cast-iron 5,700,000 By my trial. —T.T. 
* L’Art de Batir, tome iy, part ii. p. 514, 
Experi- 
