126 



A. W. Duff — Secondary Undulations 



utes, apparently identical with the oscillations shown by the 

 official gauge in the harbor, the other a series of very rapid 

 oscillations having a period of only 35 seconds. 



Figure 1. — Examples of regular secondary undulations. 1, Pictou ; 2, Forteau 

 Bay; 3, Yarmouth at low tide (examine with page inverted); 4, Yarmouth at 

 high tide; 5, St. John; 6, Grindstone Island (as near an approach to regularity 

 as could be found). The vertical scale is different for different curves. 



10. Quaco, N. B. (about 20 miles farther up the Bay of 

 Fundy than St. John). Three different records of secondary 

 undulations were obtained, giving in all three cases a mean 

 period of 12*5 m. 



This completes the list of Bay of Fundy stations. Halifax 

 is the only station not on either the Bay of Fundy or the Gulf 

 of St. Lawrence, and may be next discussed. 



Halifax, N. S. (on Halifax Harbor, Atlantic Coast of N. S.) 

 Here secondary undulations are nearly always present through 

 the whole range of the tide. Frequently they are very irregu- 

 lar and often of great amplitude, but to an eye accustomed to 

 the curves representing the composition of simple harmonic 



