54 THE TIDES oF THE BAY OF FUNDY—MURPHY. 
4. The heights of the tides are less in mid ocean and are 
greatly augmented where coast lines converge. (Hxamples from 
Dana’s Dynamic Geology.) 
Referring to the chart before us, it will be seen that the 
co-tidal lines of Whewell follow and keep nearly parallel with 
the Nova Scotia coast as we would expect (1), and extend in 
like order along the shore of Massachusetts. 
Our Nova Scotia coast extends its dip or slope far out to 
sea, and receives the advancing tidal roll, lifting it somewhat by 
the force of its own forward movement along the incline, 
until it breaks gently on the beach. A little later on, the same 
advancing volume sends its flood teeming in like manner 
along the Massachusetts and New England coast. Along 
Nova Scotia shore to Cape Sable it runs upward to the beach. 
Along Massachusetts coast it trends and runs in like manner to 
Cape Cod. Between these points it passes on without retarda- 
tion or hindrance into the bay. These capes or prominences 
mark, respectively, the juncture of the flood tides, where partially 
arrested and in motion, and the commencement of the rips or 
rotary currents which they generate. (2.) Sailing directions 
say: — “ The ebb stream across Nantucket shoals begins a short 
time before the tide has ceased to rise by the shore, and runs in a 
direction a little eastward of south, with no interval of slack 
water. Itthen gradually attains its greatest velocity, in a 
direction between south and west, after which it slackens, 
altering its direction a little westward of north. This is the 
commencement of the flood stream which gradually attains its 
greatest velocity, changing its direction to between north and 
east, or contrary to that of the ebb stream, after which it slackens 
and runs to the southward as before, thus completing an entire 
circuit in the direction of the hands of a watch. The flood 
and ebb streams are of equal duration, each running about 64 
hours, their minimum velocity being about one fourth of the 
maximuni.” 
Now, let us see how the tides disport themselves at the 
eastern entrance from Cape Sable to Briar Island. “The flood 
