194 Kindle — Note on Bottom Currents in Lake Ontario. 



The writer's observations on bottom currents were made on 

 the south side of Prince Edward Island in Wellington Bay, 

 near the town of Wellington.* Wellington Bay is a roughly 

 crescent-shaped indentation on the south shore of Prince Edward 

 Island with a maximum width of about eight miles. The 

 water deepens very gradually, the fifty-foot contour generally 

 lying nearly two miles from shore. The current observations 

 were made in this bay about one and one-third miles southwest 

 of the old pier at Wellington in thirty feet of water, while 

 using apparatus for taking ripple-mark moulds under water. 

 On the date of the observations (July 9th) the surface of the 

 lake and the air were absolutely calm until nearly noon, when 

 very light air currents became perceptible. The quiet atmos- 

 pheric conditions which prevailed are worthy of note because 

 the writer's observations were made under the conditions of a 

 dead calm, the reverse of those described by Clarke, who attrib- 

 uted the currents observed to the influence of winds blowing 

 at the time. On putting overboard the heavily weighted metal 

 ripple-mark mould, the presence of a strong undercurrent mani- 

 fested itself by immediately pulling below the surface the 

 wooden float attached to the end of the line used in hauling up 

 the apparatus. The float, which was of pine wood 2 / x2-J // x-J", 

 was pulled down 12' or 15' below the surface by the strong ten- 

 sion of the current on the line and kept at that depth from 9.30 to 

 10.30 a.m. During the next half hour the current slackened, 

 the float approaching the surface. From 11 to 11.15 the float 

 remained on the surface, showing a current trending as before 

 but much weaker, with a direction of N. 60° W. (Mag). After 

 11.15 the current strengthened somewhat and shifted to due 

 west (Mag.) At 12, when observations ceased, the current was 

 strengthening and running at right angles (west) to the very 

 light breeze which sprung up just at noon. Summing up these 

 details we may say that this current had a maximum velocity 

 of probably four and one half miles an hour, which it maintained 

 under the atmospheric conditions of a dead calm when the sur- 

 face of the lake was as smooth as a sheet of ice. Both the 

 velocity and direction of the currents were greatly altered while 

 the atmospheric conditions remained unchanged at that local- 

 ity, thus showing that they bore no relation to local air currents. 

 This current where observed traversed a sandy bottom and it 

 could not fail when running at the maximum strength noted to 

 move constantly a film of sand grains across the bottom, thus 

 making it an important factor in spreading sediments widely 

 over the lake. 



The bottom currents are well known to the deep water fisher- 

 men of the lake, who call them tides. The writer was told by 



* In making these observations the writer was assisted by Mr. E. J. Whit- 

 aker. 



