A phenomenon no less marvellous was seen by Professor Vince, of Cambridge, and another gentleman, on the 6th of August, 1806, at Ramsgate. The summits _v w x y_ of the four turrets of Dover Castle are usually seen over the hill AB, upon which it stands, lying between Ramsgate and Dover; but on the day above-mentioned, at seven o’clock in the evening, when the air was very still and a little hazy, not only were the tops _v w x y_ of the four towers of Dover Castle seen over the adjacent hill AB, _but the whole of the Castle, m n r s, appeared as if it were situated on the side of the hill next Ramsgate_, and rising above the hill as much as usual. This phenomenon was so very singular and unexpected, that at first sight Dr. Vince thought it an illusion; but upon continuing his observations, he became satisfied that it was a real image of the Castle. Upon this he gave a telescope to a person present, who, upon attentive examination, saw also a very clear image of the Castle as the Doctor had described it. He continued to observe it for about twenty minutes, during which time the appearance remained precisely the same; but rain coming on, they were prevented from making any further observations. Between the observers and the land from which the hill rises there was about six miles of sea, and from thence to the top of the hill there was about the same distance. Their own height above the surface of the water was about seventy feet. [Illustration: _Fig. 31._] This illusion derived great force from the remarkable circumstance, that the hill itself did not appear through the image, as it might have been expected to do. The image of the castle was very strong and well defined, and though the rays from the hill behind it must undoubtedly have come to the eye, yet the strength of the image of the castle so far obscured the background, that it made no sensible impression on the observers. Their attention was of course principally directed to the image of the castle; but if the hill behind had been at all visible, Dr. Vince conceives that it could not have escaped their observation, as they continued to look at it for a considerable time with a good telescope. [Illustration: _Fig. 32._] Hitherto our aërial visions have been seen only in their erect and natural positions, either projected against the ground or elevated in the air; but cases have occurred in which both erect and inverted images of objects have been seen in the air, sometimes singly, sometimes combined, sometimes when the real object was invisible, and sometimes when a part of it had begun to show itself to the spectator.