3. A white and blue flag, half white and half blue, indicates local rain
or snow. (See Fig. 15.)
4. Black triangular flag indicates a change in temperature. (See Fig.
16.)
5. White flag with a square black center indicates cold wave. (See Fig.
17.)
When No. 4 is placed above No. 1, 2, or 3, it indicates warmer weather;
when below, colder; when not displayed the temperature is expected to
remain stationary.
The following flag warnings are used along the Atlantic and Gulf coasts
to notify inhabitants of this section of the country of impending
danger.
=Fig. 18. The Small Craft Warning.= A red pennant indicates that
moderately strong winds that will interfere with the safe operation of
small craft are expected. No night display of small craft warnings is
made.
=Fig. 19. The Northeast Storm Warning.= A red pennant above a square red
flag with black center displayed by day, or two red lanterns, one above
the other, displayed by night (Fig. 19A), indicates the approach of a
storm of marked violence, with winds beginning from the northeast.
=Fig. 20. The Southeast Storm Warning.= A red pennant below a square red
flag with black center displayed by day, or one red lantern displayed by
night (Fig. 20A), indicates the approach of a storm of marked violence
with winds beginning from the southeast.
=Fig. 21. The Southwest Storm Warning.= A white pennant below a square
red flag with black center displayed by day, or a white lantern below a
red lantern displayed by night (Fig. 21A), indicates the approach of a
storm of marked violence, with winds beginning from the southwest.
[Illustration:
Fig. 24
]
=Fig. 22. The Northwest Storm Warning.= A white pennant above a square
red flag with black center displayed by day, or a white lantern above a
red lantern displayed by night (Fig. 22A), indicates the approach of a
storm of marked violence, with winds beginning from the northwest.
=Fig. 23. Hurricane, or Whole Gale Warning.= Two square flags, red with
black centers, one above the other, displayed by day, or two red
lanterns, with a white lantern between, displayed by night (Fig. 23),
indicate the approach of a tropical hurricane, or of one of the
extremely severe and dangerous storms which occasionally move across the
Great Lakes and Atlantic Coast.
[Illustration:
Fig. 25
]
We have installed at our manufacturing plant a high-class weather
station, with equipment of the latest United States Weather Bureau
standard pattern, and are able to send out weather signals by wireless
from our own wireless station twice daily, at 4 P. M. and 7 P. M., to
all boys owning a wireless outfit. The indications are taken from our
own instruments. A description of these instruments and the method of
recording the indications will give you an insight into how the various
government weather stations arrive at their forecasts.
[Illustration:
Fig. 26
]
On the roof of the factory is a weather vane (Fig. 34) twenty feet high,
which is connected electrically with a register in our weather office.
The register is of the quadruple type (Fig. 45), and is capable of
recording wind direction, wind velocity, rainfall, and sunshine on the
same form or sheet. Thus, we know the wind direction and can deduce
certain things relating to the weather. Mounted on the wind vane support
is an anemometer (Fig. 36), an instrument for measuring the velocity of
the wind. A rain gauge (Fig. 49) on the roof catches the precipitation,
and for every one hundredth of an inch of rainfall, a small tipping
bucket empties its contents into a receiver and a record is made on the
form in the quadruple register.
The same pen that records the rainfall also records the number of hours
of sunshine during a day, for it is not a common thing to have rain and
sunshine at the same time.
A hygrothermograph (Fig. 43) records on a form the temperature and
amount of humidity in the atmosphere.
A barograph (Fig. 44) records the pressure of the atmosphere. For
determining the pressure, we also have a mercurial and aneroid
barometer, which will be described later on.
You can readily see that it is a simple matter to obtain the weather
indications.
[Illustration:
Fig. 27
]