Flagstaff Hill Maritime Museum and Village
Equipment - Stevenson Screen, Thomas Stevenson, ca. 1910
... automatic weather station... for weather readings at the Cape Otway Light Station in southwest... platinum resistance probe AWS automatic weather station Rotronic AG ...
Stevenson screens were first introduced in Australia in the 1880s and were widely installed by 1910. The screens have been used to shelter and protect thermometers and other meteorological instruments from rain and direct heat while the holes and double-louvre walls allowed air to flow around them. Sometimes other meteorological instruments were included in the weather stations, so there were different Stevenson Screen sizes.
This authentic, original Stevenson screen was previously owned by the Australian Bureau of Meteorology and was used for many years for weather readings at the Cape Otway Light Station in southwest Victoria. The Lighthouse Keepers recorded the readings for minimum and maximum temperatures at 9 a.m. every day from January 1865 until April 1994. The equipment was sheltered in a Stevenson Screen from 1902 until April 15 1994, when the mercury thermometer was replaced by a platinum resistance probe within an Automatic Weather Station (AWS). This Stevenson screen is one of the two screens that then became redundant. The other Stevenson screen was kept to display to visitors. Lightkeepers were no longer required at the Cape Otway Light station either, due to the automated system.
The meteorological instruments donated with the screen were used for measuring temperature and humidity. They are mounted on a metal bracket that fits across the screw holes on the screen’s internal frame. The glass-covered Relative Humidity (RH) sensor was made by the renowned precision instrument maker, Rotronic AG of Switzerland, which was founded in 1965. The firm made its first electronic temperature and humidity instrument in 1967.
Meteorological records have been collected in Australia from the 1800s. The records were collated, published and used as a basis for weather forecasts. Many sectors, such as maritime and agriculture industries, have relied on these figures for making important decisions. The quality and placement of the meteorological instruments used to measure temperature and humidity are of utmost importance for accuracy.
In early colonial times, there were no national standards for meteorological instruments that would allow for accurate figures and comparisons. Once the Bureau of Meteorology was established (around 1908 to 1910) the department installed Stevenson screens throughout Australia, many at lighthouses and light stations, and the measuring instruments were standardised.
The Stevenson Screen was named after its inventor, Scottish Civil Engineer Thomas Stevenson (1818-1887) who was also the father of Robert Louis Stevenson, author. Stevenson developed the small thermometer screen around 1867. It had double-louvred walls around the sides and a top of two asbestos sheets with an air space between them and was thickly painted with a white coating that reflected the sun’s rays. This design was modified in 1884 by Edward Mawley of the Royal Meteorological Society. Standards were set for the locations of the screens and instruments, including their distance above ground level and the direction the door faced.Stevenson screens played a significant part in providing a standardised shelter for all meteorological instruments used by the Australian Bureau of Meteorology from about 1910 until 1994. The readings from the instruments gave the meteorological statistics on which weather forecasts throughout Australia were based.
This Stevenson screen was used locally at Cape Otway, along the Great Ocean Road in southwest Victoria, so contributed towards our local forecasts and weather warnings.Stevenson screen, original, from the Australian Bureau of Meteorology’s weather station at the Cape Otway Lighthouse. The screen is a white wooden cupboard with a slanted cover raised above the top. The top has ten drilled ventilation holes, and the sides and door are made of downward-slanting double louvres. Two brass hinges join the door to the lower edge of the screen and a metal fitting at the top edge allows for a padlock closure. The screen is supported on four short legs, each with a hole drilled from side to side for fitting to a frame. Inside the screen are two wooden frames fitted with hooks and screws. The floor has three boards; one across the back and one across the front at the same level, and a board wider than the space between these boards is fitted higher, overlapping them slightly.
Inside the screen, a pair of electronic instruments with short electric cables is mounted on a metal bracket with drilled holes in it.
One of the instruments is a Relative Humidity (RH) probe. It is 26 cm long and is a glass tube with a filter on one end and an electrical connection on the other. It has inscriptions on its label, showing that was made by Rotronic AG, Switzerland.
The other instrument is a Resistance Temperature Device (RTD) thermometer. It is 22.5 cm long and has a narrow metal probe joined to a hexagonal metal fitting.
A brass plate on the front of the screen has impressed inscriptions. The screen is Serial Number 01/C0032, Catalogue Number 235862.Stamped into brass plate "CAT. NO. / 253862 / SERIAL NO. 01/C0032"
On instrument’s electrical fitting; “CD2” [within oval ‘+’ above S] “Serie693 op65 / 220/380V~16A”
On instrument’s glass; “rotronic ag” “SWISS MADE” “CE / CH-8303 / Bassersdorf”
Symbol for [BARCODE]
“ART NO MP 101A_T4-W4W”
“POWER 4.8.30VDC“
“OP. RANGE: 0-100%RH/-40+60° C”
“OUT H 0-100% 0-1V”
“OUT T -40+60°C -0.4..+0.6V”
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Flagstaff Hill Maritime Museum and Village
Bendigo Historical Society Inc.
Waverley RSL Sub Branch