Keywords: astronomy 1920s schools slides round circle lunar black background disk blackandwhite curve black and white Slide produced by the Province of Ontario Picture Bureau, probably in the 1920s, for use in Ontario schools. Donated to the Community Archives of Belleville and Hastings County by Mike and Sue Mills in October 2015. Slide produced by the Province of Ontario Picture Bureau, probably in the 1920s, for use in Ontario schools. Donated to the Community Archives of Belleville and Hastings County by Mike and Sue Mills in October 2015. |