result of the lack of sunshine on the morning of June 26. The changes in 

 oxj'gen content were reflected in changes in free carbion dioxide and pH. 

 Free carbon dioxide was highV at Station 250, but the excess was small at 

 Station 252, and was entirely removed at Station 25U. The pH ranged from 

 7.7 at the river to 8.0 at Station ?5U. Methyl orange alkalinity was l52 

 parts per million at the river. 111 parts per. million at the range lights, 

 and only 95 parts per million at the harbor lighthouse. This change in 

 methyl orange alkalinity indicates that there is considerable mixing of 

 the water from the river v/ith that from, the lake, -ven within Maumee Bay. 



On July 17, the current was again out of the river and conditions at the 

 three stations were essentially the same as on the earlier date. The data 

 for August 3 are incomplete, since Station 25U is not represented and certain of 

 the analyses are lacking for the other stations. There was no current in the 

 river at the time samples were taken at Station 250. Judging by the relative- 

 ly high content of oxygen (UO per cent), the current had been flowing into the 

 river and was about to undergo a reversal. If the current had been outward 

 just previously, it is probable that the oxygen would have been somewhat 

 lower. At Station 2$2, oxj'-gen content and pH were high. 



On August 23 the flow was outward, but in this case oxygen depletion at 

 Station 250 was less marked than on June 26 and July 17. At the outer sta- 

 tions oxygen was very high and the carbon dioxide deficit and pH were also 

 high. Conditions at the two stations were almost the same. As on June 26 

 there was a pronounced decrease in methyl orange alkalinity with increased 

 distance from the river. On July 17 there was little change between the two 

 inner stations. 



When the samples were taken on Septenber 7, the water was flowing from 

 the bay into the river, and oxygen was nearer the saturation point than at 

 any time for which data are available in 1929. Free carbon dioxide was 

 relatively low (but see footnote Ii) and the pH high. At Stationr 252 and 25Ii, 

 conditions were, as on the preceding date, the kind one would expect to find 

 in the open lake, far from sources of pollution. On October h there was no 

 noticeable current at Station 250. It is probable that it had been into the 

 river a short time before for the water was at almost the same point of oxygen 

 saturation as on September 7. The changes with increased distance from the 

 river were much like those observed on earlier dates. 



Season of 1930 

 The data of 1929 showed that there was a decided improvement in condi- 



k/ Owing to the brown color of the water at Station 250, considerable diffi- 

 culty was encountered in detecting the end-point in titration. The values 

 recorded for this station on June 26, July 17, and August 23 are probably 

 too high. On later dates the difficulty was overcome largely, if not 

 entirely. 



97 



