258 Mr Sang <>n the Construction of Circular Towers, 



1 -^ 



Here we observe at once that 



n nep log (w) = c ; whence, 



^neplog-r-r = ^ + 



Now, taking the weight all round, 



dw = 2'!e^ tdl\ while, from the above equation, 



71) — e ^ -^ 



dw 



n 



i(:.^.) ..<",$-.),.. 



and dl=^ oJ''^ ^^ 



dw — -^ jJ^ ~ dz ; so that 



-0 



^= 



vz 



JJl^^P + ^'^ 



irz'^ (w) 

 This expression gives the thickness infinite at the summit. 



Of the Belation of Tradition to Talcetiology. By the Rev. 

 William Whewell, B. D.* 



1. Importance of Tradition. — 'Since the Palaetiological 

 Sciences have it for their business to study the train of past 

 events produced by natural causes down to the present time, 

 the knowledge concerning such events which is supplied by the 

 remembrance and records of man, in whatever form, must havo 



* From Professor Whewell's valuable work, entitled, " The Philosophy of 

 the Inductive Sciences founded upon their History." 1840. Vol. 2. 



