appear to meet at the vanishing point B. But at and about this point the line A B is intercepted by the undulating, or fluctuating surface of the water; the degree of which is variable, being sometimes very great and at others inconsiderable, and having to pass over the crest of the waves, as at H, is obliged to become A H, instead of A B, and will therefore fall upon a ship, lighthouse, or other object at the point S, or higher or lower as such objects are more or less beyond the point H. It is worthy of note that the waves at the point H, whatever their real magnitude may be, are _magnified_ and rendered more obstructive by the very instrument--the telescope--which is employed to make the objects beyond more plainly visible: and thus the phenomenon is often very strikingly observed--that while a powerful telescope will render the sails and rigging of a ship when beyond the point H, or the optical horizon, so distinct that the very ropes are easily distinguished, not the slightest portion of the hull can be seen. The “crested waters” form a barrier to the horizontal line-of-sight, as substantial as would the summit of an intervening rock or island. In the report which appeared in the _Western Daily Mercury_, of Oct. 25, 1864, the following observations were also recorded:--“On the sea-front of the Camera house, and at an elevation of 110 feet from the mean level of the sea, a plane mirror was fixed, by the aid of a plumb-line, in a _true vertical position_. In this mirror the distant horizon was distinctly visible on a level with the eye of the observer. This was the simple fact, as observed by the several members of the committee which had been appointed. But some of the observers remarked that the line of the horizon in the mirror rose and fell with the eye, as also did every thing else which was reflected, and that this ought to be recorded as an _addendum_--granted. The surface of the sea appeared to regularly ascend from the base of the Hoe to the distant horizon. The horizon from the extreme east to the west, as far as the eye could see, was parallel to a horizontal line.” The following version was recorded in the same journal, of the same date, and was furnished by one of the committee who had manifested a very marked aversion to the doctrine that the surface of all water is horizontal:--“A vertical looking-glass was suspended from the Camera and the horizon seen in it, as well as various other objects reflected, rising and falling with the eye. The water was seen in the glass to ascend from the base of the Hoe to the horizon. The horizon appeared parallel to a horizontal line.”