[w. BELL DAWSoxl TIDES IN GULF AND RIVER ST. LAWRENCE 67 



EXPLANATIOX OF THE PLATES. 



The accompanying plates will serve to illustrate the character and 

 progress of the tides throughout the Gulf and Lower St. Lawrence. The 

 tide curves given in these plates are reductions from the actual traces 

 obtained from the self-recording tide gauges. The vertical scale of the 

 gauge at each station is adapted to the local i-ange of the tide. The 

 time used throughout is Standard time for the 60th meridian, or four 

 hours slower than G-reenwich Mean Time. Each series of tides is thus 

 a simultaneous set, in absolute lime. 



The positions of the principal tidal stations themselves, and the sec- 

 ondary stations of 1896, are shown on the outline map, Plate I. 



The four principal stations at St. Paul island, Anticosti, Father 

 Point, and Quebec, form a series extending from the main Gulf entrance 

 to the head of the St. Lawrence estuary, a distance of 600 miles ; and 

 the character of the tide in its progress on this main route is shown in 

 Plate IL; and in the first half of Plate III. the simultaneous Atlantic 

 tides at Halifax and in the Sti-ait of Belle Isle, are given for comparison. 

 These are spring tides in October, I89G, which have an unusually great 

 range, as the moon was in perigee at the time. 



In the latter half of Plate III. and in Plate IV., a set of spring tides 

 in July is folio î^ed from the Atlantic through Cabot strait, and along 

 Northumberland strait, to show the character of the tides in that region. 

 The tide curves are taken from the simultaneous records obtained at 

 Halifax, St. Paul island. Souris, Pictou, and Charlottetown. The tides 

 at Carleton are also given for comparison. At Pictou and Charlotte- 

 town, the diurnal inequality is strongly marked in tliese tides, as the 

 moon's declination was then near its maximum. 



The character of the tides on the open shore of the Gulf is given in 

 Plate v.. which shows a set of spring tides in November, extending from 

 Cabot strait along the north coast of Prince Edward Island to Miramichi 

 and Chaleurs bay. These are from the stations at St. Paul island, 

 -St. Peter's, P.E.I., Neguac, N.B., and Carleton, Que. In parts of this 

 region the tides are very flat at the neaps ; but these tides are unusually 

 high even for spring tides, because of the nearness of the perigee to the 

 new moon. The reversal of the diurnal inequality on the two sides of 

 the Gulf is also very noticeable ; the moon's declination being near its 

 maximum. 



The astronomical conditions at the time of these tidal oliservations 

 &re as follows, in Standard time for the 60th meridian, Civil reckoning : 



For July 24, 25, 26; 1896 Plates III and IV. 



Full Moon, .July 24f7. Wi. 4.ô»j. Apo(,'ec, .July Wd. IHh. 

 Moon <at ma.ximum declination south, July 21(7. 17/i. 



