[w. B8LL DAWSON] TIDES IN GULF AND RIVKR ST. LAWRENCE 55 



of the next three highest and lowest. This is to eliminate cxce])tional 

 values due to wind disturbance, as was done on the Lower St. Lawi-ence, 

 in the case of observations extending over a whole year. The result is as 

 follows : — 



Strait of Belle Isle, at Forteau Bay. (Tide later than at Halifax.) 



Difference in the time of H. W. between this strait and Halifax, ranges from 



Oh. Aâm. to 4h. 01m. 

 Riinge in the ditference, ^h. 16m. Average difference = lh. ô4m. 



Luni-tidal interval ranges from 8h. 18m. to Uh. 4t)m. 

 Range in the interval, 3h. 81m. Average interval=i)h. .57m. 



The range in both cases is too great to make the comparisons of 

 practical value. By further comparisons, from which the wind disturb- 

 ance is more carefully eliminated, and the variation in diurnal inequality 

 is allowed for, it may be possible to obtain a better result. 



The same difficulty is met with in the case of the tidal current in the 

 strait. In 1894, while the surveying steamer was anchored in the strait, 

 good observations of the turn of the current were obtained during periods 

 when the currents were undisturbed by the wind ; in all 16 at high 

 water, and 12 at low water. On these, two series of comparisons were 

 based ; tirst, between the turn of the current and the time of the tide at 

 Forteau bay ; and second, between the turn of the current and the 

 moon's transit. The range in the ditference of time amounted, however, 

 to 2'' 35'" in each case. (See details of comparisons given in Annual 

 Eeport, Department of Marine, 1895 ; pages 97 and 98.) It would thus 

 appear that the time at which the current turns when undisturbed by 

 the wind, can be found without gi-eater error by direct comparison with 

 the time of the moon's transit, than by comparison with the time of high 

 •and low water at Forteau bay in the strait itself. (See note p. QQ.') 



It is evident that Cabot strait, which forms the main entrance by 

 which the tides enter the Gulf of St. Lawrence from the Atlantic, is of 

 the tirst importance from a tidal point of view. The best position that 

 could be found for a tide gauge was on St. Paul island ; and the gauge 

 was built into a break in the cliffs, which affords a certain amount of 

 shelter. It has been difficult to maintain, and has been twice destroj'ed 

 by winter storms in three years. It was expected that the tide would 

 have the same chai-aeter as at Halifax, and that a constant difference in 

 the time of the tide between the two places could be obtained. Careful 

 com])arisons were also made with Brest, France ; Sandy Hook at New 

 York; and St. John, N.B., in the hope of obtaining a constant tidal 

 difference with some well established station ; but these endeavours were 

 without result, as the variation in such tidal differences is so great that 

 no reasonable approach to constancy can be obtained. 



