Float barograph-
A type of recording siphon barometer. The mechanically magnified motion of a float resting on the lower mercury
surface is used to record atmospheric pressure on a rotating drum.
Frigorimeter-
An instrument designed to measure the physiological cooling power in milligram- calories. It consists of a blackened copper sphere, diameter 7.5 cm, the surface of which is maintained electrically at 36.5°C against
the heat losses due to all meteorological conditions of the ambient air.
Float type rain gauge-
A class of rain gauge. in which the level of the collected rainwater is measured by the position of a float resting on the surface of the water. This instrument is frequently used as a recording rain gauge
by connecting the float through a linkage to a pen that records on a clock-driven chart.
Frost point hygrometer-
An instrument similar to the dewpoint hygrometer, but especially suited for low frost points.
Fulchronograph-
A device for the measurement of lightning-stroke current as a function of time. It consists of a number of magnetic links mounted on the perimeter of a rapidly rotating wheel that is located close to the conductor bearing the lightning surge. The resolution of the instrument is sufficient to
determine current peaks as a function of time, but not the current wave shape.
