XIV ROYAL SOCIETY OF CANADA 



tides enter the gulf from the Atlantic. The resulting irregularity in the 

 gulf is in marked contrast with the even progress of the tide up the 

 estuary of the St. Lawrence when once it enters the mouth of the river. 



As the southwestern side of the gulf is the more important, arrange- 

 ments were made last season (1896) to take obsei'vations for tidal ditfer- 

 ences throughout the region extending from Gaspé, along the gulf coast 

 of New Brunswick, through Northumberland Strait, and around Prince 

 Edward Island. The object of these observations was to determine how- 

 far south of Gaspé and in the Bay des Chaleurs the tides could be referred 

 by constant differences to Anticosti and Quebec, and where the irregu- 

 larities due to diurnal inequality first manifested themselves, and 

 therefore to which of the principal stations the tides in this region could 

 best be referred. 



For the purposes of this comparison, the tide gauge at St. Paul Island, 

 €ommanding Cabot Strait, was essential ; and as it had been twice 

 destroyed by winter storms in three years, on account of its exposed 

 situation, it was necessary to obtain the required observations without 

 delay. A tide gauge had also been erected at Halifax in the previous 

 season, and the gauge at Anticosti had been put in good order ; and as 

 comparisons with any of these might be required, it was advisable to 

 obtain the new observations while they continued in good working order. 



A series of twelve stations was selected in the region i-eferred to, and 

 at eight of these self- registering instruments were placed, and staff read- 

 ings were taken at the others which were relatively of less importance. 

 The erection of these temporary gauges and the superintendence of the 

 observations was ontrnsted to Mr. H. M. Mackay, assistant on the tidal 

 survey. A very valuable series of observations was thus obtained, 

 especiall}' because of its simultaneous character. In working them up, 

 an exhaustive series of comparisons has been made with the principal 

 tidal stations. (The results of these comjDarisons, and the progress of the 

 tide throughout the gulf, are given in a paper prepared by Mr. Dawson 

 for Section III.) 



The seven principal stations have been in continuous operation 

 throughout the year, without any interruption of consequence. The 

 ^hief cause of anxiety results from a feature in the construction of the 

 recording instrument which is common to all forms of tide gauge now 

 in use. The driving clock forms an integral part of the instrument, and 

 if it requires cleaning or repair the instrument has to be entirely 

 removed and sent away to some city. The inconvenience resulting from 

 this is specially felt at the more isolated stations, which are inaccessible 

 during the winter months ; and the most serious interruiDtions that have 

 occurred have been occasioned by the failure of the driving clock. 



A form of recording instrument has now been devised by Mr. 

 Dawson which obviates the uncertainty and expense connected with the 



