AS APPLIED TO WORKS OF CONSTRUCTION. 263 
beams it may be as well to show the relationship between it and 
the modulus of rupture thus—the moment of flexure produced b 
‘a central load Won a beam resting upon supports / apart == 
a = Mt R=iab@t 
. poe 
f= ita “ss 
The modulus of rupture is therefore six times as great as this 
co-efficient. e breaking central weight can therefore be 
calculated from the following formula ;-— 
, eg oe 8 ee 
"2 ae hae Bone ey 
e mean values of f for ironbark timber used in the Mint 
experiments are as follows:— 
I. ironbark from Berrima, Eucalyptus leucoxylon 
f = 18,30 
18,: ; 
White ironbark from  Berrima, Eucalyptus  crebra 
17,136 ib. ; 
Ironbark from Albury, Lucalyptus — siderophloia 
3,734 tb. 
i) 
$ 
ae 39, 
In the experiments made by Mr. J. Whitton /£ = 13,953 hb. 
In the experiments made by the Railway Bridges Inquiry 
Commission # = 12,222 th, : 
n experiments made by the Author on specimens 34 in. by 1} in. 
and 3 in. by 2 in., tested in University machine on supports, 4 ft. 
apart, the mean value of £ = 15,000 ib : 
The specimens tested by the Author were cut from the remains 
ransverse Stiffness.—The stiffness of a beam or its resistance 
to deflection may be investigated in the following manner :— 
et + = radius of curvature. 
t Jf = moment of flexure. 
Let J = moment of inertia. 
