gton
method of replacing sand in the filters, and it is worthy of most
careful thought and attention. If the process described can be
carried on with success and safety, it will prove to be a long and
progressive step in the methods of operation. The difficulty,
however, is in determining from any short-term runs whether such a
process can be continued permanently without impairing the
efficiency of the sand bed. Apparently good conditions may change,
after a few years' trial, and be followed by unsafe results and
predicaments. This replacing of sand with whatever dirt and detritus
may travel with it in the carrying water is certainly not equivalent
to the care with which it has been understood that sand should be
deposited in filters. It is not comparable with the care with which
it is placed, when wheeled from a washer, where dirty water
overflows the lip, or where it is placed by a machine restorer in
the filter, where the transporting water also overflows the weir and
is carried to the sewer.

These cheap and rapid methods of doing the work, advanced in the
interests of economy, and the idea that sand filters, receiving
polluting waters, can operate at higher rates than those which we
have demonstrated, and, therefore, have been led to believe are
safe, is a speeding up of the whole organization and of operating
conditions. It is like speeding up a machine for the purpose of
getting a greater output, with the usual result that fast running
means quicker wearing out of both man and machine. Quicker
operations generally mean carelessness in doing the work, especially
in municipal service. Carelessness is engendered by the thought that
such work can be handled in a rough and rapid way, and, further, by
the ridicule of all these things, which we have learned to be
careful about, as old-fogyish, out-of-fashion, and archaic.
Carelessness in operation breeds contempt for the art. Some of the
less efficient filter plants, from the standpoint of effect on the
public health, may reflect such ill-considered methods

_Economy with Efficiency in Operation._--It is particularly important to
find out whether one can secure the desired economy, and, at the same
time, the required efficiency. The development of efficiency in every
line of human endeavor is receiving much attention at present, and not
the least cause for this is the growing recognition of the demand for a
high standard of service for the expense caused. One of the