August 1-9, to 20.6" (69.1° F. ) during 

 August 10-17, and then decreased to 19.3" 

 (66.7" F.) during August 20-September 12. 

 The maximum was 21.0° (69.8* F.) recorded 

 on August 8 and 17, 



Most of the subsurface temperatures 

 (81 percent) followed the direction of 

 change of the surface temperatures, some 

 (32 percent) at all depths to the bottom 

 but the vast majority (68 percent) down to 

 varying depths from aibout 4 to 35 meters 

 (13 to 115 ft.). The temperatures of the 

 waters below these upper levels either 

 shifted in contrast to the surface temper- 

 atures (76 percent) or remained constant 

 (24 percent). In a few instances the tem- 

 peratures of the lowest levels were again 

 reversed. 



A temperature of 5° (41° F.) lowered 

 gradually with the advance of the season 

 although occasionally it descended rather 

 suddenly beyond the general level of the 

 period. This 5-degree temperature descended 

 from cibout 4 meters (13 ft.) on June 3 to 

 lower levels, reaching depths just below 

 20 meters (66 ft.) by the middle of June. 

 These depths averaged 18.4 meters (60 ft.). 

 This temperature continued to descend to 

 depths that ranged, excluding one or two 

 extremes, from 25 to 35 meters (82 to 115 

 ft.) with an average of 31.6 meters (104 

 ft.) during June 27-July 9, from 40 to 55 

 meters (131 to 180 ft.) with an avercige of 

 48.8 meters (160 ft.) during July 12- 

 September 1, and from 50 to 80 meters (164 

 to 262 ft.) with an average of 60.8 meters 

 (200 ft.) during September 2-12. 



A temperature of 10° (50* F.) was not 

 recorded until June 10 near the surface. 

 It then descended gradually from an average 

 of 5,1 meters (17 ft.) during June 14-17 

 to an average of 16.3 meters (54 ft.) dur- 

 ing June 27-July 8, to 20.1 (66 ft.) during 

 July 9-27, to 27 (89 ft.) during July 28- 

 September 1, and to 29.3 (96 ft.) during 

 September 2-12. 



Temperatures below 4.0° (39.2° F.) 

 were recorded until July 9 only at stations 

 deeper than 90 meters (295 ft.). The mini- 

 mum temperature of 3.8° (38.8° F.) was 

 reported only on June 3 and 9 at depths of 

 60 meters (197 ft.) and beyond. Bottom 

 temperature did not exceed 4.0° (39.2° F.) 

 in depths greater than 82 meters (269 ft.) 

 with one exception (August 5) until Septem- 



ber 2, 1932, when thereafter they ranged 

 from 4.0° to 4,5° (39.2° to 40,1° F,) and 

 averaged 4.3° (39.7° F.) . In the water less 

 than 80 meters (262 ft.) the 1932 tempera- 

 tures varied from 4,0° to 4,3* (39.2° to 

 39.7° F.) with an average of 4,1° (39,4° F,) 

 through July 8, From July 19 to August 20 

 they ranged from 4.0* to 4.9° (39.2° to 

 40,8° F,) and averaged 4,5° (40.1* F,) 

 excluding the high temperatures recorded 

 at the isolated stations (255, 257) about 

 20 miles northeast of Charlevoix. Their 

 August bottom temperatures varied from 6,6° 

 to 9.0° (43,9° to 48,2° F, ) and averaged 

 7.5° (45,5° F.). 



The waters did not warm up enough in 

 1932 to develop a thermocline until June 14. 

 It did not extend much beyond 5 meters (16 

 ft.) until at least after June 17. It was 

 usually found between 12 and 20 meters (39 

 and 66 ft.) during June 27-July 27 and be- 

 tween 18 and 30 meters (59 and 98 ft.) dur- 

 ing July 30-September 12. The thermocline 

 was at times eliminated at widely separated 

 stations particularly during July 7-12. It 

 did, however, persist after July. No dif- 

 ferences were observed between shallow and 

 deep stations with respect to the depths 

 and disappearance of thermoclines during 

 the same period. Double thermoclines oc- 

 curred on five dates between July 28 and 

 August 17 at 1 deep eind 4 shallow stations 

 at depths between 14 and 33 meters (46 and 

 108 ft.). 



It is of interest to note that the 

 temperatures of the thermoclines also 

 tended to change with the advance of the 

 season. The minimum and maximum tempera- 

 tures of the thermoclines of June 14-17 

 that had formed in the upper 5 meters (16 

 ft.) averaged 10,5° and 16,1° (50,9° and 

 61,0° F,), As the thermocline descended 

 the averages at first decreased to 8.6° 

 and 12.3° (47.5° and 54.1° F.) (June 27- 

 July 14 ) , then slowly rose to 9.2° and 15.1" 

 (48.6° and 59.2° F.) (July 19-August 4) 

 and to 11.0° and 17.6° (51.8° and 63.7° F.) 

 (August 5-September 12). The thermal gra- 

 dients ranged from 2° to 10° (4° to 18° F.) 

 and covered depth intervals that varied 

 from 1 to 8 meters (3 to 26 ft,). During 

 the above four periods between June 14 and 

 September 12 the averages were respectively 

 5,6° (10° F.) and 4.1 meters (14 ft.), 3.5° 

 (6° P.) and 2.7 meters (9 ft.), 5.7° (10° 

 F.) and 3.3 meters (11 ft.), and 6.4° (12° 

 F.) and 4.3 meters (14 ft.). It may also 



28 



