496 



PROFESSOR CHRYSTAL 



remains to leeward has much the same prominent periods as we observe to windward, 

 viz. -4 m to -5 ni ; but it is obvious that the intervening promontory has screened oft' a great 



3o 



m.H. 



/r hts 



yfjX'CtCn.'KtcL'nj /3-q 05 



Fio. 19. 



part of the vibrations. The part thus screened off could only consist of surface waves of 

 short length, and could not consist either of longitudinal or of transverse seiches. 



Again, I often watched the statolimnograph slowly inscribing indentations, such as 



