“It has been noticed as a curious fact, first, it is believed, by Mr Whitwell, that all parallelograms seen obliquely appear distorted when magnified by a telescope. The effect is to render the space between the upper and lower parallel lines apparently greater as the distance increases,—thus annihilating the usual convergence to a vanishing point, or even reproducing it in an opposite direction. It is hardly necessary to add, that this Inversion of common perspective is only apparent; a fact conclusively established by measuring the angles subtended by the two extremities of a signboard or a row of windows, when the angle evidently diminishes with distance.