31 



possibly see the importance of them when I tell you that they consist 

 in finding a certain ellipse— the ideal ellipse as it exists in the albatross 

 I have drawn. There is an elliptical curve which is to be calculated, 



o 



Fig. 8. 



and I say that the minor axis of that ellipse is the axis of the 

 greatest effect, or the axis of least action round which the wing of 

 the bird revolves. The black axis s t represented on the diagram 

 is the actual observed axis as I have found it in the wing of the alba- 



