Show tree the airet sun dial to keep time with reasonable acau racy mua have been one ot the earliest necessities ot man hence the remarkable ingenuity 0 many primi alve inventions or this purpose the utilization ot shadows an idea which had its final development in the sun dial being probably the earliest aa it was the most obvious the first sun dial must have been a tree which may be said to have stood at one end ot the path ot evolution in ing apparatus the modern chrono meter representing at the other end the final development ot such con tri vances washington correspond corre spon dence in st louis |