ther place. In this way the actual cost of the water supply can be
reduced to scarcely more than $3, the removable pump being a permanent
possession. In rocky or mountain regions the driven well is not
practicable, because the driving point is blunted and broken by the
rock and cannot pierce the rocky beds of land.

[Illustration: FIG. 139--A driven well.]

[Illustration: FIG. 140.--Diagram showing how supplying a city with
good water lessens sickness and death. The lines _b_ show the relative
number of people who died of typhoid fever before the water was
filtered; the lines _a_ show the numbers who died after the water was
filtered. The figures are the number of typhoid deaths occurring
yearly out of 100,000 inhabitants.]

188. Our Summer Vacation. It has been asserted by some city health
officials that many cases of typhoid fever in cities can be traced to
the unsanitary conditions existing in summer resorts. The drinking
water of most cities is now under strict supervision, while that of
isolated farms, of small seaside resorts, and of scattered mountain
hotels is left to the care of individual proprietors, and in only too
many instances receives no attention whatever. The sewage disposal is
often inadequate and badly planned, and the water becomes dangerously
contaminated. A strong, healthy person, with plenty of outdoor
exercise and with hygienic habits, may be able to resist the disease
germs present in the poor water supply; more often the summer guests
carry back with them to their winter homes the germs of disease, and
these gain the upper hand under the altered conditions of city and
business life. It is not too much to say that every man and woman
should know the source of his summer table water and the method of
sewage disposal. If the conditions are unsanitary, they cannot be
remedied at once, but another resort can be found and personal danger
can be avoided. Public sentiment and the loss of trade will go far in
furthering an effort toward better sanitation.

In the driven well, water cannot reach the spout unless it has first
filtered through the soil to the depth of the driven pipe; after such
a journey it is fairly safe, unless very large quantities of sewage
are present; generally speaking, such a depth of soil is able to
filter satisfactorily the drainage of the limited number of people
which a driven well suffices to supply.

[Illustration: FIG. 141.--A deep well with the piston in the water.]