Retaining their position, and keeping their eyes still fixed upon the same spot, the two gigantic spectres again stood before them, _and were joined by a third_. Every movement that they made was imitated by the three figures, but the effect varied in its intensity, being sometimes weak and faint, and at other times strong and well defined. [Illustration: _Fig. 30._] In the year 1798, M. Jordan saw the same phenomenon at sunrise, and under similar circumstances, but with less distinctness, and without any duplication of the figures.[15] [15] See J. F. Gmelin’s _Gottingischen Journal der Wissenchaften_, vol. i., part iii., 1798. Phenomena perfectly analogous to the preceding, though seen under less imposing circumstances, have been often witnessed. When the spectator sees his own shadow opposite to the sun upon a mass of thin fleecy vapour passing near him, it not only imitates all his movements, but its head is distinctly encircled with a halo of light. The aërial figure is often not larger than life, its size and its apparent distance depending, as we shall afterwards see, upon particular causes. I have often seen a similar shadow when bathing in a bright summer’s day in an extensive pool of deep water. When the fine mud deposited at the bottom of the pool is disturbed by the feet of the bather, so as to be disseminated through the mass of water in the direction of his shadow, his shadow is no longer a shapeless mass formed upon the bottom, but is a regular figure formed upon the floating particles of mud, and having the head surrounded with a halo, not only luminous, but consisting of distinct radiations.