1886.] on Properties common to Fluids and Solid Metals. 



401 



of Mr. B. Baker, in a recent paper on the Forth Bridge.* He 

 says, " If the thing were practicable, what I should choose as the 

 material for the compression members of a bridge, would be 34 

 to 37-ton steel, which had been previously squeezed endwise, in the 



Fig. 5. 



Fig. 6. 



direction of the stress, to a pressure of about 45 tons per square 

 inch, the steel plates being held in suitable frames to prevent 

 distortion." He adds, " My experiments have proved that 37-ton 

 steel so treated will carry as a column as much load as 70-ton 



Fig. 7. 



Fig. 8, 





steel in the state in which it leaves the rolls, that is to say, not 



previously pressed endwise At least one half of the 42,000 



tons of steel in the Forth Bridge is in compression, and the same 

 proportion holds good in most bridges, so the importance of 

 gaining an increased resistance of 60 per cent, without any sacrifice 



■ Jonrn. Iron and Steel Inst.' vol, ii. 1885, p. 497. 



2 D 2 



