190 ROYAL SOCIETY OF CANADA 



point out that the turn of the tide may influence the wind, as that the 

 wind may cause the tidal stream to run longer in its own direction. 



The large mileage of wind required to produce a true wind drift is 

 further shown by the behaviour of the tidal streams with relation to the 

 wind. While anchored in mid-strait, it was often found during a strong 

 steady wind, either east or west, that the current in its ordinary change 

 from flood to ebb would set directly into the wind for the usual tidal 

 period. A strong wind has thus little appreciable effect, during a tidal 

 period of five to seven hours, in checking the current on the surface. It 

 appears to require a large mileage of wind to produce any noticeable 

 effect by its direct action on the water. 



Details of wind observations in Belle Isle strait. — As this strait is 

 unusually exposed to wind action, because of its lying in the direction of 

 the heaviest winds and also parallel to the line of the storm tracks, we 

 may give a summary of the best examples obtained during the course of 

 the observations in the two seasons of 1894 and 1906. 



In 1894 the proportionate velocities of the surface and under- 

 current were obtained by a current meter which was lowc'ed to a depth 

 of 25 to 30 fathoms, for comparison with measurements made before and 

 afterwards with the same meter at the standard depth of 18 feet, at 

 which the speed of the surface current has always been taken. 



During 19 days, from July 10 to 28, 1894, the tidal streams were 

 almost always regular and little affected by dominant flow. Wind mile- 

 age in the 19 days: 4,942 miles of westerly winds, between IST.W. and 

 S. W., and 1,300 miles of easterly winds, between N.E. and S.E. The 

 surface current when setting eastward with the prevailing winds, was 

 on the average 32 per cent stronger than the under-current, and when 

 setting westward was only 3 per cent stronger. 



Again, during nine days, September 11 to 19, the tidal streams were 

 regular, without a predominant flow either way. Wind mileage in the 

 9 days: 2,780 miles of westerly wind, and 314 miles easterly. The few 

 observations obtained showed that the surface current when setting east- 

 ward with the wind, was much stronger than the under-current; and 

 when setting westward, it was only just equal to it. 



It is to be, noted that these winds did not reverse the currents, or 

 cause them to set chiefly in their own direction. 



In the season of 1906 there were a few gales, but it is chiefly note- 

 worthy to remark the small amount of disturbance in the current which 

 they occasioned. We will therefore give the facts as concisely as pos- 

 sible. 



From June 30 to July 3 the wind as observed at Port Saunders, 

 was continuously W. and S.W., rising to 40 miles an hour on the 2nd, 



