INSTALLATION:-  The instrument is composed of two thermometers. Hang it vertically in a place

                                    where there is steady flow of air.

OPERATION:-         Fill the cistern with distilled water. Change the water frequently. The wick is

                                    changed regularly to ensure a constant flow of moisture to wet bulb.

TAKING READING & USE OF TABLE:-

1. Not down temp. of dry bulb & wet bulb thermometer.

• Calculate the difference of temperature between them. It is termed as depression value of we

      bulb.

• In the table locate reading of the dry bulb against depression value calculated at step No. 2 &

      at the intersection of the 2 columns read the % age relative humidity. For example if temp. of

      dry bulb thermometer is 30⁰ C & temp. of wet bulb thermometer is 25⁰ C. Depression value

of wet bulb is 30⁰ C -25⁰ C = 5⁰ C. Now at the intersection of dry bulb temp. 30⁰ C &

depression  value of wet bulb % age relative humidity is located. It is 65%.

REF. DOCUMENT HYGROMETER TABLE