The Toronto Magnetic and Meteorological Observatory was the nerve centre for the Dominion's Transit of Venus (ToV) campaign in 1882. That campaign was designed, organized, and directed by Charles Carpmael, the director of the observatory, superintendent of the Dominion's Meteorological Office, and first President of the reconstituted RASC from 1890-1894. The campaign involved thirteen observing stations, distributed from Charlottetown to Winnipeg. In the event, only five of those stations were able to contribute meaningful observations, and Toronto was not among them. This is doubly ironic, for not only was the campaign directed from there, but also because Carpmael had convinced his political superiors to fund his acquisition of a high quality 152mm O.G. Thomas Cooke refractor specifically to observe the ToV. Carpmael went on to author the official report of the Dominion's ToV campaign; [Charles Carpmael,] Report of the Canadian Observations of the Transit of Venus. 6th December, 1882 (Ottawa[?]: Her Majesty's Printer[?], 1882[?]).
This plaque (1910) commemorates Toronto's participation in the 1882 ToV campaign, and the Cooke telescope, among other things. Its text sins by omission, for the reader would not know that the 1882 ToV was anything but a success in cloud covered Toronto!
Photograph by R.A. Rosenfeld