Because of z'r.e -ea^.sr depth (7.0 meters), and the action of 

 waves and the river ciirrent, the tenperature is usiially nearly unifcrx. 

 frcrs siarface to bottom. This conditiori is reflected in the chemical 

 results, which show only rninor differences between the surface and 

 bottoa sa-Tiples. In general the contoit of oxygen was hj.gh. Of the 25 

 saizzjles, more than half showed a per cent of satirration above 90, and only 

 three showed a percentage less than 80. There was a deficiency of free 

 carbon dioxide in ."nost of the sanples of 152B and 1929, while in 1930 

 there was usually a slight excess, as previously noted for stations in 

 the Island Section, The pH of .-Tcst of the sanples was 8,0 or rx)re, and 

 ODne was less than 7,9, Methyl orange alkalinity was consistently low 

 at this station. Only one sample showed nore than 90 parts per ndllion. 

 The sample was taken on Jxily 9, 1929 when there was a strong southwest 

 wind blowing. It seenis probable that the wind set up a current which 

 carried lake water from the west shore to the region of Station 126, 

 for at the mouth of the i*iver (Bar Point Lightship) the methyl orange 

 alkalinity on the same day was only SI4. parts per million. With the 

 eMception of the sample of July 9, the data in Table k2 may be regarded 

 as representing conditions in water from Detroit River, 



In 193c sanples were t-aken in t,he river itself at Station 219, 

 which is located at the south end of Bois Blanc Island, near the 

 Canadian shore of the river. The data obtained on six dates are shown 

 in Table U3. 



The data show clearly that chemical conditions at this point 

 were satisfactory on every date th^t sairoles were taken. There was 

 always rxjre than 3 parts per rdllion of dissolved oxygen, representing 

 nore than 90 per cent of saturation on at least five of the dates, 

 and probably on the sixth also. The data are negative with regard to 

 pollution. At thds point in the river and just above it, the channel 

 is narrow and the ciorrent is swift. As a result the water is subject to 

 constant mxing and there is abundant opportunity for aeration. 



The United States side of the river is rrore densely populated 

 than the Canadian side, consequently it receives a larger amount of 

 sewage. Also the current is .Tore sluggish, offering less opportunity 

 for replenishmsit of oxygen by contact with the air. It seemed possible, 

 then th^t the water on the United States side of the lower part of the 

 river would show a very low content of oxygen. No saaples were taken 

 on that side during the present investigation, but a few sanples are 

 available from the unpublished report by Professor Reighard, Table hh 

 shows the results obtained in the lake and lower river on August 13, 1920. 



12 li 



