A wheel set in motion on an almost
frictionless bearing of metalline, runs without perceptible abatement
of velocity, until one begins to involuntarily question whether it
will ever stop. In the all but free winds that roll with minimized
friction in the higher atmosphere, there seems to be a self-moving
force; so persistent is simple momentum in a mass so infinitesimally
obstructed and so infinitely wheeled. An active current of air in a
ventilating flue is only less perfect in the same conditions; and so
it is quite conceivable, and not incredible, that such a current may
be gradually established and thenceforward permanently maintained by a
small motor flame barely more than enough to overbalance the minimized
friction. This is not a supposed or theoretically inferred fact, like
the facts of ventilation sometimes alleged by theorists. On the
contrary, the theory I have offered is merely an attempt to explain
facts that I have witnessed and that anyone can verify with the
anemometer. But the _theory_ by no means covers the art and mystery of
ventilation; for ventilation is truly an _art_ as well as a mystery.
The art lies in a consummate experience of the sizes, proportions, and
forms of flues, their inlets, expansions, and exits, with many other
incidental adaptations necessary, in order to insure under _all_
circumstances the regular exhaustion of any specific volume of air
required, per minute. And this art has by one man been achieved. It
would be a double injustice if I should neglect from any motive to
inform my audience to whom I am indebted for what I know about
ventilation practically, and even for the knowledge that there is any
such fact as a practicable ventilation of houses; one who is no
theorist, but who has felt his way experimentally with his own hands,
for a lifetime, to a practical mastery of the art to which I have
attempted to fit a theory; every one present who is well informed on
this subject must have anticipated already in mind the name of Henry
A.
Pages:
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135