Wortkington & Cole. 



Phil. Trans., A, Vol. 194. 



Series XVIII. 



Fig. 1. 



Fig. 2. 



Fig. 3. 



Fig. 1. 



Series XIX. 

 Fig. 2. 



Fig. 4. 



Fig. 5. 



Fig. 4. 



Fig. 3. 



Fig. 6. 



