... part of which is plane 41 A plane figure is a figure all points of which are in the same plane 42 Plane figures which are bounded by straight lines are called rectilinear figures; by curved lines, ... represented to the eye by a fine dot, and named by a letter, as A (Fig 2) A line is named by two letters, placed one at each end, as BF A surface is represented and named by the lines which bound ... according to Act of Congress, in the year 1888, by G.A WENTWORTH in the Office Of the Librarian of Congress, at Washington Copyright, 1899 By G.A WENTWORTH ALL RIGHTS RESERVED 67 10 The Athenæum...