The following gentlemen were elected to associate member- 

 ship, as proposed at last meeting— Heber Livermore, Dr. Johr 

 H. Jenks ; and Theo. S. Case to corresponding membership. 



The Academy then adjourned. 



March 16, 1885. 



The Academy met Monday evening, March i6th, 1885, Presi- 

 dent Nipher in the chair, and the following members present: 

 Messrs. Walker, Hambach, Leete, Tivy, Wheeler, Moore, Brown, 

 Potter, Gray, Foote, Sander, Allderdice, Pritchett, and Engler. . 

 After the reading and approval of the minutes of the last meet- 

 ing. Prof. H. S. Pritchett gave an account of the work of the Ob. 

 servatory of Washington University in connection with the U. S. 

 Geological Survey in determining longitudes, in the west and 

 south, which form the basis of a topographical map. A descrip- 

 tion of the plan of the U. S. Survey was given, the progress of the 

 work to the present time indicated, and the importance of the survey 

 as the basis of geological work explained. Mr. Pritchett said that 

 in Missouri only a commencement had been made, and that at 

 the present time we had no topographical map of the State. In 

 fact we possess a better topographical map of the central portion 

 of the Moon than of the State of Missouri. The time determina- 

 tions at this observatory had an average probable error of o.oi ^ 

 sec. on each night. 



Mr. Pritchett remarked that preparations were about completed 

 for beginning the work of determining a prime meridian for the 

 Republic of Mexico by telegraphic signals between the Observa- 

 tory of Washington University and the Observatory of the City of 

 Mexico — a ditsance of 2,000 miles. 



Prof. Potter remarked that the question had often been pre- 

 sented whether sewage introduced into the river here would pol- 

 lute the water ; or, in general terms, whether a running stream 

 could purify itself by the oxidation of organic matter which might 

 be thrown into it. There were a few well known chemists, nota- 

 bly Dr. Franklin of London, who were disposed to answer this 

 question in the negative ; but the weight of opinion seemed to be 



