An instrument used for measuring geometric angles. See radio direction-finder.

An instrument used to measure and record earthquake vibrations and other earth tremors.

The maximum distance, usually horizontally, at which a given object or light source is just visible under particular conditions of transmittance and background luminance.

(1) The ratio of the speeds of a chemical reaction at two temperatures differing by 10

Precipitation falling from a cloud, usually in wisps or streaks, but evaporating before it reaches the ground.

A conically shaped, copper rain gauge shield.

A metallic element of atomic weight 200.6 1, unique (for metals) in that it remains liquid under all but very extreme temperatures.

A device used to switch electrical current at a selectable setpoint temperature.

An instrument for measuring temperature by utilizing the variation of the physical properties of substances according to their thermal states. Thermometers may be classified into types according to their construction; deformation thermometer, electrical t ...

See hydrologic accounting.

Capacity of a soil or other surface to be penetrated by water sinking into the ground under the force of gravity. It thus expresses the rate of percolation.

The state of the weather with respect to its effect upon the kindling and spreading of forest fires.

An instrument for the measurement of the rate of ice accretion on an unheated body.

The distance or length of flow of the air past a point during a given interval of time.

An instrument used to reveal but not necessarily measure the presence of an electrical quantity. It is used to display the output of a sensing element after suitable amplification and modification. Sometimes called display.

The change in the measured transducer output caused by changes in ambient temperature. Usually expressed a percentage of full scale.

A power supply which achieves its output regulation by means of one or more active power handling devices which are alternately placed in the "off" or "on" states. It is more efficient than linear supplies which vary the conduction of power devices to ach ...

Not a linear function of the relevant variables.

Wind with a speed between 48 and 55 knots (55 and 63 mph), Beaufort scale number 10.

The visibility along an identified runway, determined from a specified point on the runway with the observer facing in the same direction as a pilot using the runway. Compare to runway visible range.