Thomas Leopold "Carbide" Willson 1860-1915
Born in Oxford County, Upper Canada, and largely self-educated, Willson became a noted inventor in fields ranging from the generation of electricity, through electro-chemistry and metallurgy, to production of fertilizers. His international reputation and considerable fortune derived from the discovery, in 1892, of a method to mass produce calcium carbide as was done in this building. Acetylene, generated from this compound, was used both as an illuminant and a source for other industrial hydrocarbons. Willson's discovery thus laid a basis for much of the early twentieth century's chemical industry.
Plaque via Alan L. Brown's site Ontario Plaques. Full page here.