What is this plaque? Found on the base of an old bank building in Toronto

Undecided what it’s. My guess is that it's details about the architect or constructing or maybe geographical data? It's concerning the measurement of a human hand and is discovered on a financial institution constructing inbuilt 1913 by architect Victor Daniel Horsburgh (https://www.flickr.com/photographs/57156785@N02/7314866870)