34d 



Histofy of Mechanical Inventions and 



I have observed in a great number of my experiments, that 

 the modulus of torsion bears a near delation to the weight of 

 the wood when dry, whatever may be the species ; and that 

 for practical purposes we may obtain the deflection (5) from 



the specific gravity («.) Thus 



300006/^ s 



Table of the Modulus of Torsion in Metals. 



Iron, English (wrought) 



Iron, English (wrought) 



Iron, thin hooping 



Steel, 



Steel, 



Steel, 



Iron cylinder. 



Iron cylinder. 



Iron square. 



Iron square. 



Iron square. 



Mean of Iron and Steel, 



Specific 

 gravity. 



Modulus of 

 Torsion. 

 Pounds. 



1810000 

 1740000 

 1916000 

 1984000 

 1648000 

 1618000 

 1910000 

 1700000 

 1617000 

 1667000 

 1951000 



1779090 



