Curvature of the Earth's Surface Small 320×281 Medium 640×562 Large 1024×899 Download Tiff Original 2400×2106 | (2.5 MB) Description If the earth were flat, as soon as an object appeared on the horizon we would see the upper and lower parts at the same time; but if it were curved, the top parts would first be seen. Keywords curve, earth, geography Galleries Astronomy Source: Edwin J. Houston, The Elements of Physical Geography, for the use of Schools, Academies, and Colleges. (Philadelphia: Eldredge & Brother, 1891) 13