78 



IOWA ACADEMY OF SCIENCES. 



The sewage of the college is generally very concentrated 

 when compared with the sewage of other places. The 

 sewage analyzed by the Massachusetts state board of health 

 gave the following interesting results: 



While the college sewage is more concentrated than that 

 of many of the larger cities in the East, that of some of the 

 western cities which contain manufactures may be expected 

 to have sewage stronger than that of the college. In a 

 recent investigation of the sewage of Marshalltown the 

 following results were obtained and will show the com- 

 position of sewage of this nature: 



*Thi'Se re.siilts obtained by different methods, giving much higher results than that 

 used for state college. (The temperature of the determination being 80" C. ) 



