SURVEYS OF TIDES AND CURRENTS IN CANADIAN WATERS. 



Tidal and Current Survey. 



In. this survey, an important advance has been made by the pur- 

 chase of the steamer Gulnare to enable the investigation of the xîurrents 

 to be resumed. Tlie region, requiring most immediate investigation 

 was taken up to begin with; namely, the waters aroimd the south-eastern 

 coasts of Newfoundland, on the line of our most frequented steamship 

 route. The currents in tliis region were examined last season, from 

 May to September, under the personal supervision; of Dr. W. B. Dawson, 

 the engineer in charge of the Survey. Special attention was given 

 to the question of indraught into the larger bays on the south coast, 

 and to the behaviour of the Poilar current which follows the eastern 

 coast. For this work the D. G. S. Gulnare was equipped with appli- 

 ances for deep sea anchorage, and apparatus of a modern type, in some 

 ways specially devised for the purpose. At anchorages carefully chosen, 

 the speed of the currents was measured, and the direction noted every 

 half hour, day and night. The observations also included the under- 

 current, the density and temperature of the water, the mileage and 

 direction of the wind, and a continuous record of the tide on a self- 

 registering gauge placed in a harbour in the region, for comparison 

 with the set of the current. Solar azimuth observations were alsol 

 taken to determine the magnetic variation. 



The behaviour of these currents is very varied, and they were found 

 to be so weak as to be readily influenced by the wind; but by a systematic 

 reduction of the results. Dr. Dawson has prepared a report which de- 

 scribes the currents as concisely as possible, wliile avoiding techni- 

 calities. It may be allowable to note briefly some of the results, which 

 are of more general imterest from a hydrographie point of view. 



Nature of the Currents. — The currents are almost invariably less 

 than one knot. As a rule, they veered widely and were irregular in 

 direction; and with so low a speed they were readily influenced by the 

 wind. There were three elements to distinguish: — (1) Any general 

 tendency to set in one direction more than in others. (2) Any tidal 

 influence, which might show itself either as a marked change in the 

 direction of the set. or as a period in which a variation in velocity would 

 recur. (3) The influence of the wind in disturbing the usual behaviour 



