d’esprit was published, in the “Southern Literary Messenger,” about three weeks before the commencement of Mr. L’s in the “New York Sun.” Fancying a likeness which, perhaps, does not exist, some of the New York papers copied “Hans Pfaall,” and collated it with the “Moon-Hoax,” by way of detecting the writer of the one in the writer of the other.
As many more persons were actually gulled by the “Moon-Hoax” than would be willing to acknowledge the fact, it may here afford some little amusement to show why no one should have been deceived—to point out those particulars of the story which should have been sufficient to establish its real character. Indeed, however rich the imagination displayed in this ingenious fiction, it wanted much of the force which might have been given it by a more scrupulous attention to facts and to general analogy. That the public were misled, even for an instant, merely proves the gross ignorance which is so generally prevalent upon subjects of an astronomical nature.
The moon’s distance from the earth is, in round numbers, 240,000 miles. If we desire to ascertain how near, apparently, a lens would bring the satellite, (or any distant object,) we, of course, have but to divide the distance by the magnifying, or more strictly, by the space-penetrating power of the glass. Mr. L. makes his lens have a power of 42,000 times. By this divide 240,000 (the moon’s real distance,) and we have five miles and five-sevenths, as the apparent distance. No animal at all could be seen so far; much less the minute points particularized in the story. Mr. L. speaks about Sir John Herschel’s perceiving flowers (the Papaver rh[o]eas, &c.,) and even detecting the color and the shape of the eyes of small birds. Shortly before, too, he has himself observed that the lens would not render perceptible objects of less than eighteen inches in diameter; but even this, as I have said, is giving the glass by far too great power. It may be observed, in passing, that this prodigious glass is said to have been moulded at the glass-house of Messrs. Hartley and Grant, [i]n Dumbarton; but Messrs. H. and G[.]’s establishment had ceased operations for many years previous to the publication of the hoax.
On page 13, pamphlet edition, speaking of “a hairy veil” over the eyes of a species of bison, the author says—“It immediately occurred to the acute mind of Dr. Herschel that this was a providential contrivance to protect the eyes of the animal from the great extremes of light and darkness to which all the inhabitants of our side of the moon are periodically subjected.” But this cannot be thought a very “acute” observation of the Doctor’s. The inhabitants of our side of the moon have, evidently, no darkness at all; ·429· so there can be nothing of the “extremes” mentioned. In the absence of the sun they have a light from the earth equal to that of thirteen full unclouded moons.
The topography throughout, even when professing to accord with Blunt’s Lunar Chart, is entirely at variance with that or any other lunar chart, and even grossly at variance with itself. The points of the compass, too, are in inextricable confusion; the writer appearing to be ignorant that, on a lunar map, these are not in accordance with terrestrial points; the east being to the left, &c.
Deceived, perhaps, by the vague titles, Mare Nubium, Mare Tranquillitatis, Mare Fæcunditatis, &c., given to the dark spots by former astronomers, Mr. L. has entered into details regarding oceans and other large bodies of water in the moon; whereas there is no astronomical point more positively ascertained than that no such bodies exist there. In examining the boundary between light and darkness (in the crescent or gibbous moon) where this boundary crosses any of the dark places, the line of division is found to be rough and jagged; but, were these dark places liquid, it would evidently be even.
The description of the wings of the man-bat, on page 21, is but a literal copy of Peter Wilkins’ account of the wings of his flying islanders. This simple fact should have induced suspicion, at least, it might be thought.
On page 23, we have the following: “What a prodigious influence must our thirteen times larger globe have exercised upon this satellite when an embryo in the womb of time, the passive subject of chemical affinity!” This is very fine; but it should be observed that no astronomer would have made such remark, especially to any Journal of Science; for the earth, in the sense intended, is not only thirteen, but forty-nine times larger than the moon. A similar objection applies to the whole of the concluding pages, where, by way of introduction to some discoveries in Saturn, the philosophical correspondent enters into a minute schoolboy account of that planet:—this to the Edinburgh Journal of Science!
But there is one point, in particular, which should have betrayed the fiction. Let us imagine the power actually possessed of seeing animals upon the moon’s surface;—what would first arrest the attention of an observer from the earth? Certainly neither their shape, size, nor any other such peculiarity, so soon as their remarkable situation. They would appear to be walking, with heels up and head down, in the manner of flies on a ceiling. The real observer would have uttered an instant ejaculation of surprise (however prepared by previous knowledge) at the singularity of their position; the fictitious observer has not even mentioned the subject, but speaks of seeing the entire bodies of such creatures, when it is demonstrable that he could have seen only the diameter of their heads!
It might as well be remarked, in conclusion, that the size, and particularly the powers of the man-bats (for example, their ability to fly in so rare an atmosphere—if, indeed, the moon have any)—with most of the other fancies in regard to animal and vegetable existence, are at variance, generally, with all analogical reasoning on these themes; and that analogy here will often amount to conclusive demonstration. It is, perhaps, scarcely necessary to ·430· add, that all the suggestions attributed to Brewster and Herschel, in the beginning of the article, about “a transfusion of artificial light through the focal object of vision,” &c., &c., belong to that species of figurative writing which come[s], most properly, under the denomination of rigmarole.
There is a real and very definite limit to optical discovery among the stars—a limit whose nature need only be stated to be understood. If, indeed, the casting of large lenses were all that is required, man’s ingenuity would ultimately prove equal to the task, and we might have them of any size demanded. But, unhappily, in proportion to the increase of size in the lens, and, consequently, of space-penetrating power, is the diminution of light from the object, by diffusion of its rays. And for this evil there is no remedy within human ability; for an object is seen by means of that light alone which proceeds from itself, whether direct or reflected. Thus the only “artificial” light which could avail Mr. Locke, would be some artificial light which he should be able to throw—not upon the “focal object of vision,” but upon the real object to be viewed—to wit: upon the moon. It has been easily calculated that, when the light proceeding from a star becomes so diffused as to be as weak as the natural light proceeding from the whole of the stars, in a clear and moonless night, then the star is no longer visible for any practical purpose.
The Earl of Ross telescope, lately constructed in England, has a speculum with a reflecting surface of 4071 square inches; the Herschel telescope having one of only 1811. The metal of the Earl of Ross’ is 6 feet diameter; it is 5½ inches thick at the edges, and 5 at the centre. The weight is 3 tons. The focal length is 50 feet.
I have lately read a singular and somewhat ingenious little book, whose title page runs thus:—“L’Homme dans la lvne, ou le Voyage Chimerique fait au Monde de la Lvne, nouuellement decouuert par Dominique Gonzales, Aduanturier Espagnol, autremèt dit le Courier volant. Mis en notre langve par J. B. D. A. Paris, chez François Piot, pres la Fontaine de Saint Benoist. Et chez J. Goignard, au premier pilier de la grand’ salle du Palais, proche les Consultations, MDCXLVIII.” pp. 176.
The writer professes to have translated his work from the English of one Mr. D’Avisson (Davidson?) although there is a terrible ambiguity in the statement. “I’en ai eu,” says he, “l’original de Monsieur D’Avisson, medecin des mieux versez qui soient aujourd’huy dans la cònoissance des Belles Lettres, et sur tout de la Philosophie Naturelle. Je lui ai cette
