love's meinie. 29 



for his living- power. There is one of the long feathers 

 of robin's "wino;, and here (Fig. 1) the analysis of its 

 form. 



31. First, in pure outline (a), seen from above, it is 

 very nearly a l<Mig oval, hut with this peculiarity, that it 

 has, as it were, projecting shoulders at a 1 and a 2. I 

 merely desire you to observe this, in passing, because one 

 usually thinks of the contour as sweeping unbroken from 

 the root to the point. I have not time to-day to enter on 

 any discussion of the reason for it, which will appear 

 when we examine the placing of the wing-feathers for 

 their stroke. 



Now, I hope you are getting accustomed to the general 

 method in which I give you the analysis of all forms — 

 leaf, or feather, or shell, or liinb. First, the plan ; then J — ^ 

 the profile ; then the cross-section. 



I take next, the profile of my feather (b, Fig. 1), 

 and find that it is twisted as the sail of a windmill is, 

 but more distinctly, so that you can always see the upper 

 snrface of the feather at its root, and the under at its 

 end. Every primary wing-feather, in the fine flyers, is 

 thus twisted ; and is best described as a sail striking with 

 the power of a scymitar, but with the flat instead of the 

 edge. 



32. Further, you remember that on the edges of the 

 broad side of feathers you find alwaj's a series of undula- 

 tions, irregularly secpient, and lapping over each other 

 like waves on sand. You mio-lit at first imagine that this 



