452 



ANIMAL MECHANICS. 



we have 



(125) 



which represents a cubical hyperbola. 

 If we write 



i - w, 



t) = wn (useful effect), 



we find 



Zri = A, (126) 



which represents an equilateral hyperbola. 



If we write A = 19600, in equation (124), we can calculate 

 the following values of w, and compare them with the ob- 

 served values : — 



Mr. Jevons > Experiments {lifting Weights with Pulley). 



w. 



n (ob- 

 served) . 



n (cal- 

 culated). 



Difference. 



56 



5-7 



6.2 



- 0.5 



42 



11. 9 



II. I 



+ 0.8 



28 



23.0 



25.O 



- 2.0 



21 



37-6 



44.3 



- 6.7 



14 



III.O 



IOO. O 



4- II. O 



Cubical hyperbola, w 2 n = 19600. 



In Fig. 103, I have constructed the cubical hyperbola, 

 w 2 n = 19600, 



showing both its asymptotes, and marking with small circles 

 the observations of Mr. Jevons ; the agreement between cal- 

 culation and observation is sufficiently clotse for this class of 

 experiments. 



The relation between the useful effect and weight lifted is 

 represented by an equilateral hyperbola (126), and the useful 



