e a gravity supply is unavailable, the probable operating
expenses of the water system, cost of pumping, etc.

_Collection of Rain Water_

The collection of rain water near extensive manufacturing
establishments is not advisable, except where arrangements are
provided for either filtering or distilling the water. In the country,
rain water is pure and good, if the precaution is observed to allow
the first wash from roofs to run to waste. The rain may be either
caught on the roofs, which must always have a clean surface and clean
gutters, or else on artificially prepared catchment areas. As an
example, I quote: "All about the Bermuda Islands one sees great white
scars on the hill slopes. These are dished spaces, where the soil has
been scraped off and the coral rock exposed and glazed with hard
whitewash. Some of these are a quarter acre in size. They catch and
carry the rainfall to reservoirs, for the wells are few and poor, and
there are no natural springs and no brooks." (Mark Twain, "Some
Rambling Notes of an Idle Excursion.")

After the close of the Boer War the English sent about 7,000 Boer
prisoners of war to Bermuda, where they were encamped on some of the
smaller islands of the group, and the entire water supply for the
encampment was obtained by building artificial catchment areas as
described in the above quotation.

Sometimes, instead of building underground cisterns, rain water is
caught and stored in barrels above ground; if so, these should always
be well covered, not only to avoid pollution, but to prevent the
barrels from becoming mosquito breeders. Cisterns should always be
built with care and made water-tight and impervious. The walls should
be lined with cemented brickwork. In soil consisting of hard pan,
cisterns in some parts of the country are built without brick walls,
the walls of the excavation being simply cemented. I do not approve of
such cheap construction, particularly where the cistern is located
near a privy or cesspool. Pollution of cistern water is often due to
the cracking of the cement lining. Overflows of cisterns should never
be connected with a drain, sewer, or cesspool. Run the overflow into
some surface ditch and provide the mouth with a fine wire screen, to
exclude small animals. It is not recommended to build cisterns in
cellars of houses.

_Quality of Water Obtained from Lakes_

Lakes yield, as a rule, a supply of clear, bright, and soft water.
This is particularly