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METEOROLOGICAL APPARATUS


HYGROGRAPH



MAKER Negretti & Zambra

WHEN ca 1920 to 1940

WHAT DOES IT DO? Measures relative humidity.

HOW DOES IT WORK? Human hair changes length as it absorbs water vapour. Relative humidity is measured by this change.

Source: Meteorological Service of Canada



SNOW SAMPLER




MAKER Exco

WHEN after 1961

WHAT DOES IT DO? Measures the depth of snow and its water content.

HOW DOES IT WORK? Snow is removed with the calibrated tube and its depth is noted. The tube is then weighed to determine the water content of the snow.

Source: Meteorological Service of Canada



ANEMEVANE




MAKER James Foster, Toronto

WHEN ca 1876

WHAT DOES IT DO? This anemovane was designed by George Kingston, first director of Canada's weather service. One of the earliest remote reading instruments, it made it easier to determine wind direction. The wind turned the fans of the anemovane in the direction it was blowing. The direction was relayed through a system of shafts and gears to a dial in the observer's room below.

Source: Meteorological Service of Canada



EVENT RECORDER




MAKER Julien P. Friez

WHEN 1899 to 1913

WHAT DOES IT DO? Used with an Anemometer to measure wind speed and direction.

HOW DOES IT WORK? One needle shows the wind speed on the graph paper while the other indicates the wind direction.

Source: Meteorological Service of Canada



FORTIN BAROMETER








MAKER R. Fuess

WHEN ca 1935

WHAT DOES IT DO? Measures atmospheric pressure.

HOW DOES IT WORK? Air presses on a bulb of mercury, forcing it up a tube. Higher pressure increases the mercury level. High pressure indicates good weather.

Source: National Research Council of Canada, Instrument Division.



ASSMAN PSYCHROMETER




MAKER Casella

WHEN ca 1960

WHAT DOES IT DO? Measures humidity.

HOW DOES IT WORK? Consists of one wet thermometer and one dry one. The evaporation of the liquid on the wet one lowers its temperature. The difference of the temperature between the thermometers indicates the relative humidity.

Source: Meteorological Service of Canada



SUNSHINE RECORDER




MAKER Casella

WHEN after 1958

WHAT DOES IT DO? Measures sunshine duration.

HOW DOES IT WORK? The Sun's rays are focused by a glass sphere, burning a card. The area of card burned indicates total energy received.

Source: Meteorological Service of Canada



ACTINOGRAPH




MAKER Meteorological Service of Canada

WHEN 1950's

WHAT DOES IT DO? Measures solar and sky radiation.

HOW DOES IT WORK? This device contains two thermometers one on black metal and the other on white metal. The difference of the temperature between these thermometers indicates the solar energy level.

Source: Meteorological Service of Canada



SOLAR THERMOMETER




MAKER Taylor Instrument Co.

WHEN mid 20th century

WHAT DOES IT DO? Measures temperature.

HOW DOES IT WORK? A bulb filled with mercury is heated by the Sun's energy, causing the mercury to rise in the tube.

Source: Meteorological Service of Canada



ALIDADE




MAKER Canadian Westinghouse Co. Ltd. WHEN 1940's to early 1950's

WHAT DOES IT DO? Measures the height of clouds.

HOW DOES IT WORK? A light beam is projected onto the base of the clouds. Its length is measured to know the altitude of the clouds.


Source: Meteorological Service of Canada



For more information on our scientific instruments, contact the Curator, Physical Sciences and Medicine, David Pantalony.

Go back to Sampler of Scientific Instruments