482 
MR. W. H. BARLOW OX THE RESISTANCE OF FLEXERE 
of sustaining is little more than half its ultimate tensile strength. But although there 
exists this disproportion as regards the ultimate resistances by tension and compression, 
the force required to overcome the elasticity of the material is nearly the same, vhether 
applied as a compressive or a tensile strain ; the difference being, that the force which 
overcomes the elasticity when applied as a compressive strain, leads to the destruction 
or distortion of the material ; while in the case of the tensile strain, the elasticity may 
be overcome long before the material yields by absolute ruptui'e. 
The following experiments, made in Wooludch Dockyard by Professor Baelow, show 
the relative weights which overcome the elasticity of the metal when applied trans- 
versely, as compared with the weight necessai’y to produce the same result when applied 
by direct tension. 
Three bars, numbered 6, 6 and 7, each 2 inches square, were tested by direct tension; 
and the strain which was just sufficient to overcome the elasticity of the iron, was foimd 
to be — 
Tons per square incli of section. 
No. 5. Re-manufactured iron 9'5 
No. 6. Re-manufactured Ron, from old furnace-bars . 8'25 
No. 7. New bar by Messrs. Gordon 10 '00 
Bars of the same quality of metal having been subjected to transverse strain in a 
bearing of 33 inches, the weights which overcame their elasticity, when so applied, were 
as follows : — 
Using the tensile 
formula 
Tons. 
Mean. 
No. 5 ... 
. . . 3-00] 
3-00 
No. 5 ... 
. . . 3-OOJ 
No. 6 ... 
. . . 2-501 
2-25 
No. 6 ... 
. . . 2-Oo} 
No. 7 . . . 
. . . 3-00^ 
No. 7 ... 
. . . 2-50 
2-83 
No. 7 ... 
. . . 3-OOi 
resistance in each case for/* and obtaining the value of p from the 
Tons. 
Tons. 
No. 5 . . . 
ip=6-04 
/= 9-50 
No. 6 . . . 
<p=3-78 
f= 8-25 
No. 7 . . . 
?)=5-01 
/=10-00 
Mean . . 
^=4-94 
/= 9-25 
Mean ratio 
: 1 : -53. 
In addition to these, six other experiments are given on iron, of the quality of No. 7, 
which are as follows : — 
