of the lake (Table 23). Free ammonia and nitrite also were hij^h in the river, 

 but nitrate was unexpectedly low. Just outside the mouth of the river (Sta- 

 tion 250), free and albuminoid ammonia were still very high, but nitrite and 

 nitrate were lower than in the river. The significance of the low concentra- 

 tion of nitrite and nitrate at this station, and at others farther from the 

 river, will be taken up later. At station 2^1 there was a marked decline 

 from Station 2^0 in all forms of nitrogen except nitrate. The decline was 

 particularly large for free ammonia. Owing to the very high free ammonia at 

 Station 2 $2 on September 9, the mean value at that station was higher than at 

 Station 25l. The reason for the abundance of ammonia at Station 2^2 on that 

 date is not known. Between these two stations albuminoid ammonia decreased, 

 nitrite remained the same, and nitrate increased slightly. At Station 25U 

 free and albuminoid were lower than at any station in the group. However, 

 nitrite was unchanged from Station 252, and nitrate increased. 



It is clear from the figures in Table 33 that the water in the river and 

 at the mouth was polluted, and that there was marked i-nprovement with increasec 

 distance from the river. At Station 25U, which is 8.5 miles from the river, 

 the amoTints of the various forms of nitrogen were not greatly different from 

 the means for the Island Section (Table 22). They were very much like those 

 at Station 1^9, in the Portage River Section (Table 26). It may be said 

 that the nitrogen determinations indicate a change from heavy to light pollu- 

 tion in a distance of 8.5 miles from the mouth of the river. 



The data in Table 32 show that there were large fluctuations in the 

 amounts of nitrogen compounds at the different stations on different dates. 

 This is not surprising, particularly for the station at the mouth of the river, 

 because of the reversing currents. However, there is no evident relationship 

 between the direction of current and the amount of nitrogen at Station 250. 

 Doubtless such a relationship could be demonstrated if the direction of the 

 current during a considerable period prior to sampling were known. 



In addition to the stations listed in Table 33, four others in the Maumee 

 Bay Section were visited. The data are shown in Table 3U. Station 105 is 

 1.75 miles from the south shore of the lake and six miles southeast of Toldeo 

 Harbor Light. Station 108 is three miles from Toledo Harbor Light in the 

 same direction as Station 105. Station 233 is half a mile from the east 

 shore of Little Cedar Point. Station ll6 is 1-1/8 miles from the shore at 

 Toledo Beach, Michigan. 



It will not be necessary to dwell at length on the data from these sta- 

 tions. It will suffice to point out that they resemble closely those from 

 Stations 252 and 25ii. The rather large differences on different dates are 

 to be expected from the fact that currents would sometimes bring in an 

 unusually large volume of water from sources other than Maumee Bay. 



It may be instructive to introduce, at this point, some results of 

 a sanitary survey of Maumee River made in IB98 by the Ohio State Board 

 of Health (I899) . Chemical and bacteriological samples were taken in vari- 

 ous parts of the watershed, including the part just above the mouth. Judg- 



106 



II 



