The Meridian of Toronto
This line in the true North-South direction through the site of the Toronto Magnetic Observatory, marks the meridian for Toronto that was recognized by scientists around the world until 1908.
Each section of this beam is 3.085 metres long, equivalent to 0.1 second of arc of latitude exemplifying the high precision of the 1883 determination of the latitude and longitude of the observatory, recorded on the transit pillar nearby.
In 1840, magnetic North here was almost coincident with true North, but has drifted slowly westward since that time. By 1898 , when magnetic observations had to be abandoned at this site owing to interference from the newly electrified street railways, the variation had reached 5 degrees.