There are no evidences, in the table, that the water at Station 1^9 

 was unfavorably influenced by water from the river. There was always an 

 ample supplj'" of dissolved oxygen. The water was usually more than 90 per 

 cent saturated and never less than 8U percent. On only four occasions was 

 there an excess of free carbon dioxide, and frequently the deficiency was 

 rather marked. The lowest pH reading was 7.8. Methyl orange alkalinity was 

 consistently high, and on one date (May 21, 1929) it was much higher than any 

 value obtained in t he Island Section. In other respects the data are the 

 same kind as those found at Stations 37A, 1^8, and 8F. 



The discharge of Portage River is small, and the current reverses 

 periodically. Even when the current is out of the river, the discharged water 

 is commonly deflected by littoral currents, and does not reach Station 1$9. 

 In order to learn something about conditions in the river itself , a number of 

 samples were taken at Station l60, near shor^ at the foot of Madison Street in 

 Port Clinton (depth, 3 meters) . If the river were badly polluted, one vrould 

 expect to find chemical evidence of it at this point. 



The data as given in Table 25, afford little or no evidence of pollution. 

 On August h, when there was no noticeable current in the river, the water was 

 only 77 per cent saturated with oxygen, but similar results were occasionally 

 recorded for stations in the open lake, far from sources of pollution. On 

 August 22, when the current was directed up-river, the water was nearly satu- 

 rated, and on September l6, when the current was outward, the water was only 83 

 percent saturated. This difference may have resulted from a difference in the 

 photosynthetic activity of the algae, for the sky was clear on August 22, while 

 it was overcast on September l6. The data for free carbon dioxide and oH agree 

 with those for oxygen in failing to show definite evidence of pollution. The 

 data reported by Osburn (1926a) are much the same as those reported here. A 

 sample taken at the mouth of the river on August 9, when the current was out- 

 going, showed 6.7 parts per million of oxygen (79 per cent of saturation), and 

 pH 8.U. Stations in the lake near the river had a somewhat higher content of 

 oxygen. At one station the water was 9h per cent saturated, and the pH was 8.6. 



It should not be concluded that the river is free from pollution, but only 

 that, on the days when samples were taken, the amount of polluting matter was 

 -not sufficiently great to cause a marked withdrawal of oxj'^gen, \^th the asso- 

 ciated changes in carbon dioxide and pH. It is conceivable that under unusual 

 conditions there would be pronounced oxygen depletion in the river. But it is 

 doubtful whether such unusual conditions would ever persist long enough to 

 make the river an important contributor of oxygen-free water to the lake. 



Chloride and nitrogen 



Samples were taken at two stations in this sectionj at Station l59, a 

 short distance out from the mouth of the river, and at Station 60, in the 

 river- near its mouth. The data are shown in Table 26. 



At both stations there were marked differences in chloride and nitrogen 

 on different dates, as would be expected from the fact that the current of 

 the river reverses periodically. Because of the constantly changing condi- 

 tions here, it would be necessary to take many more samples to determine 

 averages accurately. But in spite of the small number of samples taken, the 

 results have some rather characteristic features which should be noted. 



