32 



Prof. G. H. Darwin. 



[Nov. 22 



again in v. It is again formed in vi and vii, and then becomes per- 

 manent, and is transmitted up the stem of the tree. 



Fig. 11. 



In fig. 11 the convolution is added in ii, and then remains perma- 

 nently part of the tree; but a partial convolution is added in iii and 

 iv, which is unwrapped again in v, vi, vii. 



Thus in violent oscillation the convolution is permanently added 

 just before an elongation, and in gentle oscillation afterwards. It 

 would be easy to construct a figure for an intermediate . amplitude in 

 which the convolution is added just at elongation. If the oscillation 

 gradually increases, the convolutions are permanently added sooner 

 and sooner, and at the same time the formation of convolutions and 

 subsequent unwrapping assumes more and more prominence. 



