IMPA 370251 – Wet & Dry Bulb Hygrometers

• Consisiting of dry and wet alcohol filled glass thermometers fixed on a panel .
•  By differential indication between these thermometers , humidity can be read
  from the table mounted on a panel
•  Used to measure the relative humidity in the Cargo hold .
•  Basically, two thermometers are used in this hygrometer. One thermometer
  feels the surrounding air temperature. This thermometer is called a dry bulb
  thermometer. Another mercury thermometer is used to measure the water
  temperature at the temperature of a dry bulb thermometer. This thermometer
  is called the wet-bulb thermometer. A sleeve of muslin cloth or wicking dip is
  fitted over the feeling end of the wet-bulb thermometer. The free end of this
  muslin sleeve dips in the reservoir or container filled with distilled water. The
  temperature measuring scale is mounted close to each thermometer.