Watchkeeping - Meteorology Flashcards
What is a Mason’s hygrometer?
A device containing 2 thermometers known as the wet and dry.
The thermometers are the same other than the wet has a muslin cloth attached and placed in a water reservoir.
The difference between the dry and wet will give you the depression of the wet bulb.
Go to the Mariner’s Handbook NP100 and access the dew point tables to achieve dew point temperature.
What would an equal reading of both thermometers in the hygrometer indicate?
The air has been saturated and a foggy conditions will be present.
With hygrometers both to port and starboard which one would you take the reading from?
The windward side.
What checks would you do on the hygrometer?
Ensure the mercury bulb is clean and undamaged.
The fresh water reservoir is changed weekly.
What is a stevenson’s screen?
The Stevenson’s screen is a thermometer screen which the masons hygrometer will be contained within. It provides protection from external conditions which may otherwise interfere with the instruments operation.
