FIG. 4.
Along the edge of the water, in the same canal, six flags were placed, one statute mile from each other, and so arranged that the top of each flag was 5 feet above the surface. Close to the last flag in the series a longer staff was fixed, bearing a flag 3 feet square, and the top of which was 8 feet above the surface of the water--the bottom being in a line with the tops of the other and intervening flags, as shown in the following diagram, Fig, 4.
On looking with a good telescope over and along the flags, from A to B, the line of sight fell on the lower part of the larger flag at B. The altitude of the point B above the water at D was 5 feet, and the altitude of the telescope at A above
the water at C was 5 feet; and each intervening flag had the same altitude. Hence the surface of the water C, D, was equidistant from the line of sight A, B; and as A B was a right line, C, D, being parallel, was also a right line; or, in other words, the surface of the water, C, D, was for six miles absolutely horizontal.
If the earth is a globe, the series of flags in the last experiment would have had the form and produced the results represented in the diagram, Fig. 5. The water curvating from
[paragraph continues] C to D, each flag would have been a given amount below the line A, B. The first and second flags would have determined the direction of the line of sight from A to B, and the third flag would have been 8 inches below the second; the fourth flag, 32 inches; the fifth, 6 feet; the sixth, 10 feet 8 inches; and the seventh, 16 feet 8 inches; but the top of the last and largest flag, being 3 feet higher than the smaller ones, would have been 13 feet 8 inches below the line of sight at the point B. The rotundity of the earth would necessitate the above conditions; but as they cannot be found to exist, the doctrine must be pronounced as only a simple theory, having no foundation in fact--a pure invention of misdirected genius; splendid in its comprehensiveness and bearing upon natural phenomena; but, nevertheless, mathematical and logical necessities compel its denunciation as an absolute falsehood.
The above-named experiments were first made by the author in the summer of 1838, but in the previous winter season, when the water in the "Old Bedford" Canal was frozen, he had often, when lying on the ice, with a good telescope observed persons skating and sliding at known distances of from four to eight miles. He lived for nine successive months within a hundred yards of the canal, in a temporary wooden building, and had many opportunities of making and repeating observations and experiments, which it would only be tedious to enumerate, as they all involved the same principle, and led to the same conclusions as those already described. It may, however, interest the reader to relate an instance which occurred unexpectedly, and which created such a degree of con-fusion, that he was repeatedly tempted to destroy the many memoranda he had previously made. Up to this time all his observations had been made in the direction of Welney, the bridge there affording a substantial signal point; but on one occasion, a gentleman who resided within a few miles of the temporary residence already alluded to, and with whom conversations and discussions had been repeatedly held, insisted upon the telescope being directed upon a barge sailing in an opposite direction to that previously selected. Watching the slowly receding vessel for a considerable time, it suddenly disappeared altogether! The gentleman co-observer cried out in a tone of exultation, "Now, sir, are you satisfied that the water declines?" It was almost impossible to say anything in reply. All that could be done was to "gaze in mute astonishment" in the direction of the lost vessel--
compelled to listen to the jeers and taunts of the apparent victor. After thus wonderingly gazing for a considerable time, with still greater astonishment the vessel was seen to suddenly come again into view? Obliged to admit the reappearance of the vessel; neither of us could fairly claim the victory, as both were puzzled and equally in an experimental "fix." This condition of the question at issue lasted for several days, when, one evening conversing with a "gunner" (a shooter of wild fowl), upon the strange appearance referred to, he laughingly undertook to explain the whole affair. He said that at several miles away, beyond the ferry-house, the canal made a sudden bend in the shape of the letter V when lying horizontally, and that the vessel disappeared on account of its entering into one side of the triangle, and reappeared after passing down the other side and entering the usual line of the canal! After a time a large map of the canal was found in a neighbouring town, Wisbeach, and the "gunner's" statement fully verified.
The following diagram will explain this strange, and for a time confounding, phenomenon.
A, represents the position of the observer, and the arrows the direction of the vessel, which, on arriving at the point B, suddenly entered the "reach" B, C, and disappeared, but which, on arriving at C, became again visible, and remained
so after entering and sailing along the canal from C to D. The ferry-house and several trees, which stood on the side of the canal, between the observer and the "bend," had prevented the vessel being seen during the time it was passing from B to C. Thus the "mystery" was cleared away; the author was the real victor; and the gentleman referred to, with many others of the neighbourhood, subsequently avowed their conviction that the water in the "Bedford Level" at least, was horizontal, and they therefore could not see how the earth could possibly be a globe.
