| ...
Dalecarlia | 2.2 | 50 | 5,000 | 53 | 22
Georgetown | 2.2 | 38 | 3,400 | 24 | 32
McMillan | 2.8 | 26 | 2,000 | 31 | 41
------------+-----+-----+-------+----------+----------
Totals and | | | | |
averages | 7.2 | ... | ... | 75 | 69
============+=====+=====+=======+==========+==========

While it may perhaps seem unreasonable to single out Washington as a
particular sufferer in this respect, it is highly probable that a
large share of the typhoid is still caused by secondary infection,
flies, impure milk, and private and public wells. The speaker
remembers distinctly that ten years ago, when he made an
investigation into the purity of the water of about 100 public wells
in that city, a large number of them showed unmistakable evidence of
being polluted with sewagic matter. Conclusive evidence would be
secured to dispel any doubt as to the sanitary quality of the
filtered product if hypochlorite of lime were added to the filtered
water throughout one year or throughout the typhoid months. It seems
strange to the speaker, that for this, if for no other reason, this
safe and non-injurious germicide has not as yet been used at
Washington, in view of the fact that at the present time it is being
used continuously or intermittently in the treatment of the water
supplies of scores of the most important cities of this country,
among which may be mentioned New York, Philadelphia, Cincinnati,
Pittsburg, St. Louis, and Minneapolis.

~Morris Knowles, M. Am. Soc. C. E~. (by letter).--This description
of the operation of the Washington Filtration Works is timely and of
great interest. It is ten years since the writer, in collaboration
with Charles Gilman Hyde, M. ~Am. Soc~. C. E., presented a similar
record for the Lawrence, Mass., filter. That paper was the first
complete, detailed, and continuous history of the actions and
results obtained for a long period of time with such a purification
works.[1] Since then, the art of filtration has advanced in many
ways, particularly in regard to the methods of cleaning slow sand
filters and in the accompanying processes. It is well, therefore,
again to take account of stock and see really what progress has been
made. Therefore, Mr. Hardy's paper, giving a description of the
operations of a system thoughtfully designed, after long
consideration of the problem, and of operations carried on under