1st Stevenson Screen
Environment Canada's Stevenson Screens. The first one was ventilented (motorized fan) the second one non ventilented. First screen housed two mercury filled thermometers - one dry and one wet bulb to measure air temperatures every hour. After 30 years of service they were torn down by Environment Canada technicians who flew up 1,500 miles to tear them down. We're now digitalized since 2005.