340 



ranged between 1.4 and 3.9 parts per million. The bottom figure on 

 July 88, 1922, at Spring Bay Narrows (1.4 p. p. m.) was lower than 

 the figure at Rome the day before; but both on July 3, 1922 (when 

 it was 3.3 at Spring Bay Narrows), and on August 29, 1922 (when 

 it was 3.9), a relatively large improvement had taken place in the 

 approximate five-miles distance between Rome and the foot of the lake. 

 The variation in the gage at Peoria during the period July 3 to August 

 29 was a little less than two feet. The lowest bottom dissolved oxygen 

 figures at Chillicothe were recorded on July 3, August 9, and August 

 29, on gages 11.3, 10.4, and 9.8 feet corresponding; and the highest 

 on a gage of 10.7 feet on July 27. The lowest bottom figures at Rome 

 occurred on July 3 at a gage of 11.3 feet Peoria, and on Augfust 9 at 

 gage 10.4; while the high figures (1.6 to 2.0 p. p. m.) came on July 27 

 and August 29 on gages 10.7 and 9.8 feet. 



Bottom oxygen figures slightly lower than any of these were re- 

 corded at Chillicothe and Rome and in the vicinity of Spring Bay in 

 the summer of 1920. A table comparing the channel figures from the 

 upper lake and Chillicothe for 1922 and 1920 follows. 



Bottom Dissolved O.xyoen, Mio-Ciianxei-, Upper Peoria Lake, 1920-1922 

 midsummer figures, parts per mii.liox 



• Miles below Liake Michigan. ChillicoUie is a river station just above the 

 present upper low-water boundary of the Peoria Lrfike wide-waters. 



