This detailed diagram of Trajan's column was probably drawn from a plaster
copy. Turner used the image during
his first lecture to the Royal Academy
as Professor of Perspective in 1811.
Turner discussed the problems of representing the distortion of sculptural features when viewed from below. In
this example, the spiral bas-reliefs are
at the top of a column thirty metres
high. Turner's delivery of his lectures
was apparently poor, but people came
to see the illustrations.