A. If the air be very cold it is so much condensed, that it has already parted with as much moisture as it can spare.
Q. What is the 4TH SPECIAL RULE in regard to the barometer?
A. When the barometer stands very low indeed, there is never much rain, although a fine day will seldom occur at such times.
Q. What kind of weather will it be when the barometer is unusually low?
A. There will be short heavy showers, with sudden squalls of wind from the west.
Q. Why will there be very little rain if the barometer be unusually low?
A. Because the air must be very warm, or very moist, or perhaps both.
Q. Why will there be little or no rain, if the air be very warm?
A. If the air be very warm it will have a tendency to imbibe more moisture, and not to part with what it has.