IOWA ACADEMY OF SCIENCES. 247 
into nitrates. This *being the case the question at once 
arises, why would not the system of intermittent filtration 
and of the septic tank work well together. Experience has 
taught that they do and it is to a system of this kind that 
the remainder of this paper will be devoted, taking as a 
basis the sewage system of the Iowa State College. Great 
credit is due Prof. Marston, who introduced this system in 
Iowa. 
TABULATED BACTERIOLOGICAL RESULTS. 
DATE 
From. 
TEMPERATURE. 
Manhole 
Tank. 
Effluent. 
j 
<5 
Water. 
September i.. 
September 2.. 
September 3.. 
September 4. 
September 5.. 
September 5.. 
September 5.. 
September 6.. 
September 7.. 
September 8.. 
September 9.. 
September 10.. 
September 11 . . 
September 12.. 
September 12. . 
September 12.. 
September 13. . 
September 14. . 
September 15 . . 
September 16.. 
September 17. . 
September 18.. 
September 19.. 
Septemper 19 . . 
September 19. . 
September 20.. 
Septem ber 21 . . 
September 22. . 
September 23. . 
September 24 . . 
September 25 . . 
September 26. . 
September 27 . . 
September 27. . 
September 27. . 
September 28 . . 
September 29.. 
September 30. . 
October 1 
W. E 
2, 400 
4, 800 
880 
1,320 
600 
E. E 
W. E 
E. E 
W. E 
Manhole 
9,000,000 
Tank 
1 , 800. 000 
E. E 
1,920 
1,840 
1, 5bo 
1,420 
3,800 
3,640 
2, 160 
W. E 
W. E 
E. E 
W. E 
W. E 
E. E 
Manhole 
8,600 00c 
Tank 
2, 050. 000 
E. E 
2,400 
i, 600 
2, 760 
3,96o 
3,78o 
2,920 
4,080 
W. E. 
E. E 
W. E 
W, E 
W. E 
W. E 
Manhole 
7, 260, 000 
Tank 
2, 170. 00 
W. E 
3,660 
2, 520 
2, 760 
5,400 
9, 000 
9, 120 
8,040 
8, 160 
W. E 
W. E 
W. E 
W. E 
W. E 
W. E 
E. E 
Manhole 
9,600,000 
Tank . 
6, 960, 000 
E. E 
4, 400 
4, 100 
3,800 
3,76o 
3,720 
3,720 
E. E 
E. E 
8, 815,000 
3,245,000 
3,660 
E. E 
October 2 
E. E 
October 3 
E. E ....... 
October 3 
Manhole 
4, 800, 000 
October 3 
Tank 
4,200,000 
October 4 
E. E 
5, 160 
4, 820 
5,040 
5,880 
5,400 
6, 120 
7. 280 
October 5 
E. E 
October 6 
W. E 
October 7 
W. E 
October 8 
W. E 
October 9 
E. E 
October 10 
W. E 
October 10 
Manhole 
6,480,000 
October 10 
Tank 
4, 618,000 
October 11 
E. E 
4-*- 
O IO 
OOO 
O O 
October 12 
E. E 
