100 Canon Moseley on the Descent of a Solid Body on an 



a less resistance ; and the displacement of the extremity upwards 

 will equal the sum of these several dilatations. In like manner, 



Fie. 1. 



A, 



Fig. 2. 



M 



Bi 



p 2 



if the same temperature be added to the elements of X B in 

 succession, beginning from X, each will be dilated more than the 

 one before it, and the displacement BBj of the extremity B 

 downwards will equal the sum of these several dilatations. The 

 point X will obviously be nearer to A than to B, because the 

 same thrust- of dilatation of the element at X would not be able 

 to push so great a length of the bar up the plane as it would 

 down it. 



In this state of the temperature of the plate, let a point X T 

 be taken such that, if it were divided there, the strain necessary 

 to pull the part Xj A } down the plane would just equal that ne- 

 cessary to pull X, B, up it. Let the temperature of the element 

 at Xj be so diminished as by its contraction just to produce this 

 strain, and let the temperatures of all the elements from Xj 

 to A x in succession be equally reduced. Each will contract 

 more than the one before it, because a less resistance will be 

 offered to its contraction ; and the displacement A l A 2 of Aj down 

 the plane will equal the sum of these separate contractions. In 

 the same way the displacement B L B 2 of Bj up the plane will 

 equal the sum of the separate contractions of the elements of 

 X^. The point X L will be further from A 2 than B J? because 

 the same strain of contraction of an element at X, would pull a 

 greater length of the bar down the plane than up it. It is by 



