The first of these methods yields a hypsographical, or - if the sea-bottom be included, in which case all contours are referred to a common datum line - a bathy hypsographical map. Carl Ritter, in 1806, employed graduated tints, increasing in lightness on proceeding from the lowlands to the highlands; while General F.
A third pencil traces an observation line in which a kick can be made at will by pressing any one of the electrical pushes placed about the car, and a fourth draws a datum line.
The shaded rectangles represent the distribution of shear due to the load at C, while no may be termed the datum line of shear.
I), gave during three consecutive years the respective falls shown by the height of the dotted lines above the datum line.