Keywords: Inventional Geometry page 17.png William George Spencer http //books google co uk/books id DDIDAAAAQAAJ pg PA17 img 1 zoom 3 hl en sig ACfU3U0avcjtnOOHMP2EyJuFp7D_WuKq8g ci 10 2C26 2C975 2C1454 edge 0 Google Books Publishers J C Mozley London 1860 PD-old-100 1860 books Book pages from England Geometry diagrams Schoolbooks |