APPLICATION OF CHAINS.' 



129 



The chain in 

 the common 

 way is less so* 



The flexibility is inversely as these momenta, and 

 proves the superiority of chains ; for (on the average of 

 the trials^ with the chain in the grooves. 



One pound raised 31,25 lbs. 

 With a half-worn strand-laid tarred rope, 

 three inches and a half in circumfer- 

 ence, 26,11 do. 



And with the chain in the usual way, 



only. 



24,47 do; 



It also appears (contrary to the general opinion), that r^^ic chain i 

 chains are safer than ropes ; for it is an established axiom, safer than » 

 that those bodies whose fibres are most in the direction of '*^P*' 

 the strain, are the least liable to be pulled asunder ; and 

 in our examination of the properties of a rope, we find 

 that the strands cross the direction of the strain in undu- 

 lated lines, and consequently prevent its uniform action 

 thereon. A rope is subject to this inconvenience even 

 when stretched in a direct line, but more particularly s^ 

 when bent over a pulley, as in that position the upper 

 section moving through a greater space than the under 

 one, is acted upon by the whole strain ; and hence the 

 frequent breaking of ropes in bending over pullies, from 

 the double strain overloading the strands of which thf 

 upper section is formed. 



* All the experiments were tried Vfith the same grooved pulUes. 



• VcL. XV.— Oct. 1800. S The 



