Myths and Marvels of Astronomy

by Richard A. Proctor

In a letter to the Astronomer-Royal Mr. Reddie announced that he was about to write 'a paper intended to be hereafter published, elaborating more minutely and discussing more rigidly than before the glaring fallacies, dating from the time of Newton, relating to the motion of the moon.' He proceeded to 'indicate the nature of the issues he intended to raise.' He had discovered that the moon does not, as a matter of fact, go round the earth at the rate of 2288 miles an hour, as astronomers say, but follows an undulatory path round the sun at a rate varying between 65,000 and 70,000 miles an hour; because, while the moon seems to go round the earth, the latter is travelling onwards at the rate of 67,500 miles an hour round the sun. Of course he was quite right in his facts, and quite wrong in his inferences; as the Astronomer-Royal pointed out in a brief letter, closing with the remark that, 'as a very closely occupied man,' Mr. Airy could 'not enter further into the matter.' But further Mr. Reddie persisted in going, though he received no more letters from Greenwich. His reply to Sir G. Airy contained, in fact, matter enough for a small pamphlet.

Now here was certainly an amazing fact. A well-known astronomical relation, which astronomers have over and over again described and explained, is treated as though it were something which had throughout all ages escaped attention. It is not here the failure to comprehend the rationale of a simple explanation which is startling, but the notion that an obvious fact had been wholly overlooked.

Of like nature was the mistake which brought Mr. Reddie more especially under Professor De Morgan's notice. It is known that the sun, carrying with him his family of planets, is speeding swiftly through space—his velocity being estimated as probably not falling short of 20,000 miles per hour. It follows, of course, that the real paths of the planets in space are not closed curves, but spirals of different orders. How, then, can the theory of Copernicus be right, according to which the planets circle in closed orbits round the sun? Here was Mr. Reddie's difficulty; and like the other, it appeared to his mind as a great discovery. He was no whit concerned by the thought that astronomers ought surely to have noticed the difficulty before. It did not seem in the least wonderful that he, lightly reading a book or two of popular astronomy, should discover that which Laplace, the Herschels, Leverrier, Airy, Adams, and a host of others, who have given their whole lives to astronomy, had failed to notice. Accordingly, Mr. Reddie forwarded to the British Association (in session at Newcastle) a paper controverting the theory of the sun's motion. The paper was declined with thanks by that bigoted body 'as opposed to Newtonian astronomy.' 'That paper I published,' says Mr. Reddie, 'in September 1863, with an appendix, in both thoroughly exhibiting the illogical reasoning and absurdities involved in the theory; and with what result? The members of Section A of the British Association, and Fellows of the Royal Society and of the Royal Astronomical Society, to whom I sent copies of my paper, were, without exception, dumb.' Professor De Morgan, however, having occasion to examine Mr. Reddie's publications some time after, was in no sort dumb, but in very plain and definite terms exhibited their absurdity. After all, however, the real absurdity consisted, not in the statements which Mr. Reddie made, nor even in the conclusions which he drew from them, but in the astounding simplicity which could suppose that astronomers were unaware of the facts which their own labours had revealed.

In my correspondence with Mr. Reddie I recognised the real source of the amazing self-complacency displayed by the true paradoxist. The very insufficiency of the knowledge which a paradoxist possesses of his subject, affords the measure of his estimate of the care with which other men have studied that subject. Because the paradoxist is ready to pronounce an opinion about matters he has not studied, it does not seem strange to him that Newton and his followers should be equally ready to discuss subjects they had not inquired into.

Another very remarkable instance was afforded by Mr. Reddie's treatment of the subject of comets. And here, by the way, I shall quote a remark made by Sir John Herschel soon after the appearance of the comet of 1861. 'I have received letters,' he said, 'about the comets of the last few years, enough to make one's hair stand on end at the absurdity of the theories they propose, and at the ignorance of the commonest laws of optics, of motion, of heat, and of general physics, they betray in their writers.' In the present instance, the correspondence showed that the paradoxist supposed the parabolic paths of some comets to be regarded by astronomers as analogous to the parabolic paths traversed by projectiles. He expressed considerable astonishment when I informed him that, in the first place, projectiles do not travel on truly parabolic paths; and secondly, that in all respects their motion differs essentially from that which astronomers ascribe to comets. These last move more and more quickly until they reach what is called the vertex of the parabola (the point of such a path which lies nearest to the sun): projectiles, on the contrary, move more and more slowly as they approach the corresponding point of their path; and further, the comet first approaches and then recedes from the centre of attraction—the projectile first recedes from and then approaches the attracting centre.

The earth-flatteners form a considerable section of the paradoxical family. They experienced a practical rebuff, a few years since, which should to some degree have shaken their faith in the present chief of their order. To do this chief justice, he is probably far less confident about the flatness of the earth than any of his disciples. Under the assumed name of Parallax he visited most of the chief towns of England, propounding what he calls his system of zetetic astronomy. Why he should call himself Parallax it would be hard to say; unless it be that the verb from which the word is derived signifies primarily to shift about or dodge, and secondarily to alter a little, especially for the worse. His employment of the word zetetic is less doubtful, as he claims for his system that it alone is founded on the true seeking out of Nature's secrets.

The experimental basis of the theory of Parallax is mainly this: Having betaken himself to a part of the Bedford Canal, where there is an uninterrupted water-line of about six miles, he tested the water surface for signs of curvature, and (as he said) found none.

It chanced, unfortunately, that a disciple—Mr. John Hampden, of Swindon—accepted the narrative of this observation in an unquestioning spirit; and was so confident that the Bedford Canal has a truly plane surface, that he wagered five hundred pounds on his opinion, challenging the believers in the earth's rotundity to repeat the experiment. The challenge was accepted by Mr. Wallace, the eminent naturalist; and the result may be anticipated. Three boats were to be moored in a line, three miles or so between each. Each carried a mast of given length. If, when the summits of the first and last masts were seen in a line through a telescope, the summit of the middle mast was not found to be above the line, then Mr. Hampden was to receive five hundred pounds from Mr. Wallace. If, on the contrary, the top of the middle mast was found, as the accepted theory said it should be, to be several feet above the line joining the tops of the two outer masts, then Mr. Hampden was to lose the five hundred pounds he had so rashly ventured. Everything was conducted in accordance with the arrangements agreed upon. The editor of a well-known sporting paper acted as stakeholder, and unprejudiced umpires were to decide as to what actually was seen through the telescope. It need scarcely be said that the accepted theory held its own, and that Mr. Hampden lost his money. He scarcely bore the loss with so good a grace as was to have been expected from a philosopher merely desirous of ascertaining the truth. His wrath was not expended on Parallax, whom he might have suspected of having led him astray; nor does he seem to have been angry with himself, as would have seemed natural. All his anger was reserved for those who still continued to believe in the earth's rotundity. Whether he believed that the Bedford water had risen under the middle boat to oblige Mr. Wallace, or how it came to pass that his own chosen experiment had failed him, does not appear.

The subsequent history of this matter has been unpleasant. It illustrates, unfortunately but too well, the mischief which may ensue from the tricks of those who make a trade of paradox—tricks which would be scarce possible, however, if text-books of science were more carefully written, and by those only who are really acquainted with the subject of which they treat.

The book which originally led to Mr. Hampden's misfortunes, and has misled not a few, ought to have deceived none. I have already mentioned the statement on which Parallax (whose true name is Rowbotham) rested his theory. Of course, if that statement had been true—if he had, with his eye a few inches from the surface of the water of the Bedford Canal, seen an object close to the surface six miles from him—there manifestly would have been something wrong in the accepted theory about the earth's rotundity. So, also, if a writer were to announce a new theory of gravity, stating as the basis of his theory that a heavy missile which he had thrown into the air had gone upwards on a serpentine course to the moon, any one who accepted the statement would be logically bound to admit at least that the fact described was inconsistent with the accepted theory. But no one would accept such a statement; and no one should have accepted Mr. Rowbotham's statement.