PROCEEDINGS FOR 18!)6 XIII 



also the most convenient time for our own harbours, as Standard time is 

 now used almost everywhei-e. 



The tide tables are based upon records obtained from self- registering- 

 gauges, which are specially designed to allow of their being heated to 

 prevent freezing in winter, and thus to obtain a continuous record day 

 and night throughout the year. 



The records from these gauges, after careful tabulation and reduc- 

 tion to low water datum, are forwarded to the Nautical Almanac Office, 

 London. The tidal constants are determined from them by the method 

 of harmonic analysis, and the tidal predictions for the ensuing year are 

 made by means of a tidal computing machine of special design. 



The tide tables for Halifax are at present based upon records of the 

 tide during the two years 1860 and 1861 ; and in making the calculations 

 for 1897, the record for two other years, 1851 and 1852, will be added, to 

 extend the basis from which the predictions are made. These are the 

 only existing records which are known ; but when a sufficient record is 

 obtained from the new tide-gauge erected at Halifax last season, a further 

 improvement in closer accuracy will be possible. 



The tide tables for Quebec are based upon a record extending from 

 JSTovember, 1893, to January, 1895, or a little over one complete year. 

 Their accuracy will be improved as the record becomes longer ; but as 

 they stand they are far in advance of any tables yet published. 



A good record has now been obtained also at St. John, N.B., but it 

 has not been possible so far to afford the expense of the reduction of this 

 record, and the preparation of tide tables from it. 



The tide tables for Halifax and Quebec have been supplied to the 

 following almanacs for the current year 1896 : 



The Canadian A/?Hrmac, published by the Co|)p-Clark Co., of Toronto. 



The Star Almanac, published at the Montreal Star Office, Montreal. 



Greemvood's Almanac, Y^ublished by W. N. Greenwood, Lancaster, 

 England. 



CogswelVs J^/znawrtc, published by R. H. Cogswell, Halifax, containing 

 the Halifax tables only. 



The tide tables for Quebec will also be embodied in the " Tide tables 

 and other information connected with the ship channel between Montreal 

 and Quebec," issued by the Harbour Commissioners of Montreal, and 

 supplied to the pilot service. 



With these tables, tidal differences are given as far as they could be 

 considered trustworthy. Differences applicable to the ILilifax tables ai*e 

 given for the Atlantic coast of Nova Scotia, as the actual difference in the 

 time of high water along that coast is small. 



The tidal differences from (Quebec have been extended and improved 

 for next year (1897), and in doing so all the available sources of informa- 

 tion have been utilized. For the Lower St. Lawrence, the simultaneous 



