and coagulant had
been added to the water at times when it was excessively turbid, a
considerably shorter period of subsequent sedimentation than now
exists would in all probability have rendered the water at all times
amenable to efficient and economical slow sand filter treatment.

The prejudice in Washington against the use of coagulants has also
manifested itself in other localities, but the results which have
been obtained during the past twenty years from rapid sand filters
and from slow sand filters, treating waters previously coagulated
with salts of iron or alumina, have shown how thoroughly
unreasonable were these objections. In this connection it is
interesting to note that there are in the United States more than
350 rapid sand filter plants, and that nearly 12% of the urban
population of Continental United States is being supplied with water
filtered through rapid sand filters, in connection with all of which
a coagulating chemical is used in the preparatory treatment.

~Table 24--Typhoid Fever Death Rates in Cities of the United
States with Populations in 1910 of 100,000, or More.~

Statistics gathered by correspondence and from Reports of
the Bureau of the Census, Department of Commerce and Labor,
Mortality Statistics.

~Note~.--Statistics from Birmingham, Ala., Dayton, Ohio, Fall River,
Mass., Louisville, Ky., Memphis, Tenn., Oakland, Cal., and
Providence, R. I., are not included, as they are
incomplete.

Columns:
A - Average for six years, 1900-05, inclusive.
B - Average for five years, 1906-10, inclusive.
C - Average for 11 years, 1900-11, inclusive.

====================+===============================================
| ~ Typhoid Fever Death Rate
City. | per 100,000 Population~.
+-----+-----+-----+-----+-----+-----+-----+-----
| 1906| 1907| 1908| 1909| 1910| A | B | C
--------------------+-----+-----+-----+-----+-----+-----+-----+-----
Albany, N. Y. | 20 | 20 | 11 | 19 | 15 | 25 | 17 | 21
Atlanta, Ga. | 50 | 64 | 47 | 44 | 43 | 65 | 50 | 58
Baltimore, Md. | 34 | 41 | 31 | 23 | 41 | 36 | 34 | 35
Boston, Mass. | 22 | 10 | 26 | 14 | 11 | 23 | 16 | 20
Bridgeport, Conn. | 10 | 13 | 13 | 13 | 9 | 15 | 12 | 14
Buff