196 Proeessor Whewell on the 



Sep — Sis 



•'• x = Sep y 



whence x the rate of exchange is known. 



19. In the case assumed in Art. 6, we may now calculate the 

 rate of exchange during the progress of the alteration. 



Let x t Xo x, be the rates of exchange during the 3 first years, 

 c, Sis ) (, 30/ 3 



^l 1 - s^p-^\ l -w = r^ 



(_ Sis \ C 15) 2 

 S, Sis ) n 



If the expense of transferring gold be 1 per cent., the exchange 



111 

 will be, in the 1st, 2nd, 3rd year respectively, ^^, -^, — , and 



afterwards 0. 



20. I will not quit the subject without again stating that I 

 by no means wish to attribute any mathematical certainty, or any 

 extraordinary value, to the preceding results, considered with re- 

 ference to their application to the real circumstances of human 

 affairs. I must however observe, that if they are useless and in- 

 applicable, the fault resides in the postulates which I have bor- 

 rowed from Mr. Ricardo and others, and not in the mode of 

 deducing the consequences of these principles. If these postulates 



