ANIMAL MECHANICS. 



293 



we find 



9773; 

 0.4142. 



This represents the amount of work done round the axis ST; 

 and the work done round the axis LM is 



n 2 = 0.4238. 



Hence we find 



96 

 4238 



44 



or the work done by the rotation of the wing of the Albatross 

 round its observed socket differs by only ^th part from the 

 calculated possible maximum work. This degree of agreement 

 between calculation and observation is sufficient to satisfy all 

 reasonable expectations. 



(b.) Wing of the Wood Pigeon. — The next example that I 

 shall select is the wing of the Wood Pigeon, shown in Fig. 

 78. The origin of the pectoral muscle is shown at AB, and its 

 insertion at AB' . The angle AOB is 23 0 , and the socket of 

 the wing is placed at S; the line ST being the axis round 

 which the wing-bone revolves. 



Dividing the angle AOB into six equal parts, 1 found 

 the following measurements, made in thirty-seconds of an 

 inch : — 



Wing of Wood Pigeon. 



Angle. 



l- V 



I cos 9. 



I' cos 9. 



o°.oo' 



1 \ 



59 



49 



5.20 



76 



121 



45 



10. 40 





.38 



39 



1 6. 00 



ll 5 



153 



38 



21.20 



129 



1.63 



35 



26. 40 



'43 



161 



33 



32 . 00 



156 



180 



3o 



From these measurements the following 

 lated ;— - 



values arc calcu- 



