The SciencesSundials and Their Construction--VMaterials for Construction; Calculating TimeBy Margaret Walton Mayall, R. Newton Mayall on July 1, 1934AdvertisementABOUT THE AUTHOR(S)Recent Articles by Margaret Walton MayallSundials and their ConstructionSundials and Their ConstructionSundials and their ConstructionRecent Articles by R. Newton MayallSundials and Their ConstructionSundials and their ConstructionSundials and their Construction--VI