~2i\± M. C. Szily on tlte Dynamical Signification of the 



the same, in whichever period the change happen, provided 

 only the phase be the same. Hence 



or 



^^ + 2T ; . «,. ^^2 + 2T . * ; 



and since 



T =T f , and dt = dti, 

 we shall have 



SA t .=SA oj 

 and considering the signification of SA, 



2??i(V { &^ + . . .) = Sm(/ ^' + . . . ), 

 or 



S=m[^a^ + «/%+ < s / S^]J=0. 



We arrive therefore at the result that 



i8Q = S(2iT), 



or, in words, The variation of the action of the body during a 

 pulsation is equal to the product of the period of the pidsation 

 and the quantity of energy communicated to it during that time. 

 As in this equation the variation-symbols only are preserved, 

 we can substitute differentiation-symbols for them, and write 



i.dQ = d(2iT) (La) 



If constancy of state be defined in the way in which we have 

 defined it) equation (I. a) will be valid for every body and for any 

 infinitesimal change of state. 



If the body goes through a closed series of state-changes 

 (a " cyclical process "), so that i and T at the close resume 

 the initial values, then is 



or 



§§dQ.dt=0, 



where the first integral refers to a complete oscillation, and 

 the second to an entire cyclical process. 



Equation (I. a), however, can also be integrated in another 

 way. If we divide it by i . T, we get 



S= 2 .rflogO:T), 



