Replies.
PENDULUM DEMONSTRATION OF THE EARTH'S ROTATION.
(Vol. iv., p. 129.)
I beg to send you a few remarks on the note of A. E. B., concerning the "Pendulum Demonstration of the Earth's Rotation."
Your correspondent appears to consider that the only fact asserted by the propounders of the theory, is a variation in the plane of oscillation, caused by "the difference of rotation due to the excess of velocity with which one extremity of the line of oscillation may be affected more than the other;" the probable existence of which he proves by imagining a pendulum suspended over a point half-way between London and Edinburgh, and set in motion by being drawn towards and retained over London, and thence dismissed on its course. It is clear that in such a case the pendulum would at starting be impressed with the same velocity of motion in an eastern direction which the retaining power in London had, and that its path would be the result of this force compounded with that given by gravity in its line of suspension, i.e. towards the north, and its course would therefore be one subject to easy calculation. I should imagine that this disturbing force arising from the excess of eastern velocity possessed by the starting point over that of suspension, would be inappreciable after a few oscillations; but at all events it is evident that it might readily be avoided by setting the pendulum in motion by an impulse given beneath the point of suspension, by giving to it a direction east and west as suggested by A. E. B., or by several other expedients which must occur to a mathematician.
Your correspondent proceeds by requiring that there should be shown "reasonable ground to induce the belief that the ball is really free from the attraction of each successive point of the earth's surface," and is not as "effectually a partaker in the rotation of any given point" as if it were fixed there; or that "the duration of residence" necessary to cause such effect should be stated. Now I certainly am aware of no force by which a body unconnected with the earth would have any tendency to rotate with it; gravity can only act in a direct line from the body affected to the centre of the attracting body, and the motion in the direction of the earth's rotation can only be gained by contact or connexion, however momentary, with it. The onus of proving the existence of such a force as A. E. B. alludes to, must surely rest with him, not that of disproving it with me. What the propounders of this theory claim to show is, I humbly conceive, this,—that the direction in which a pendulum oscillates is constant, and not affected by the rotation of the earth beneath it: that as when suspended above the pole (where the point of suspension would remain fixed) the plane of each oscillation would make a different angle with any given meridian of longitude, returning to its original angle when the diurnal rotation of the earth was completed; and as when suspended above the equator, where the point of suspension would be moved in a right line, or, to define more accurately, where the plane made by the motion of a line joining the point of suspension and the point directly under it (over which the ball would remain if at rest) would be a flat or right plane, the angle made by each successive oscillation with any one meridian would be the same, so, at all the intermediate stations between the pole and the equator, where the point of suspension would move in a line, commencing near the pole with an infinitely small curve, and ending near the equator with one infinitely large (i.e. where the plane as described above would be thus curved), the angle of the plane of oscillation with a given meridian would, at each station, vary in a ratio diminishing from the variation at the pole until it became extinct at the equator, which variation they believe to be capable both of mathematical proof and of ocular demonstration.
I do not profess to be one of the propounders of this theory, and it is very probable that you may have received from some other source a more lucid, and perhaps a more correct, explanation of it; but in case you have not done so, I send you the foregoing rough "Note" of what are my opinions of it.
E. H. Y.
A SAXON BELL-HOUSE.
(Vol. iv., p. 102.)
Your correspondent MR. GATTY, in a late number, has quoted a passage of the historian Hume, which treats a certain Anglo-Saxon document as a statute of Athelstan. As your correspondent cites his author without a comment, he would appear to give his own sanction to the date which Hume has imposed upon that document. In point of fact, it bears no express date, and therefore presents a good subject for a Query, whether that or any other era is by construction applicable to it. It is an extremely interesting Anglo-Saxon remain; and as it bears for title, "be leodgethincthum and lage," it purports to give legal information upon the secular dignities and ranks of the Anglo-Saxon period. This promises well to the archæologist, but unfortunately, on a nearer inspection, the document loses much of its worth; for, independently of its lacking a date, its jurisprudence partakes more of theory than that dry law which we might imagine would proceed from the Anglo-Saxon bench. Notwithstanding this, however, its archæological interest is great. The language is pure and incorrupt West Saxon.
It has been published by all its editors (except Professor Leo) as prose, when it is clearly not only rythmical but alliterative—an obvious characteristic of Anglo-Saxon poetry. And it is this mistake which has involved the further consequence of giving to the document a legal and historical value which it would never have had if its real garb had been seen through. This has led the critics into a belief of its veracity, when a knowledge of its real character would have inspired doubts. I believe that its accidental position in the first printed edition at the end of the "Judicia" (whether it be so placed in the MS. I know not) has assisted in the delusion, and has supplied a date to the minds of those who prefer faith to disquisition. The internal evidence of the document also shows that it is not jurisprudence, but only a vision spun from the writer's own brains, of what he dreamed to be constitutional and legal characteristics of an anterior age, when there were greater liberty of action and expansion of mind. The opening words of themselves contain the character of the document:—"Hit wæs hwilum." It is not a narrative of the present, but a record of the past.
The legal poet then breaks freely into the darling ornament of Anglo-Saxon song, alliteration: "On Engla lagum thæt leod and lagum," and so on to the end. As its contents are so well known and accessible, I will not quote them, but will merely give a running comment upon parts. "Gif ceorl getheah," &c. It may be doubted whether, even in occasional instances, the ceorl at any time possessed under the Anglo-Saxon system the power of equalising himself by means of the acquisition of property, with the class of theguas or gentils-hommes. But in the broad way in which the poet states it, it may be absolutely denied, inasmuch as the acquisition of wealth is made of itself to transform the ceorl into a thegn: a singular coincidence of idea with the vulgar modern theory, but incompatible with fact in an age when a dominant caste of gentlemen obtained.
It is not until the reign of Edward III. that any man, not born a gentleman, can be distinctly traced in possession of the honours and dignities of the country; an air of improbability is thus given which is increased by a verbal scrutiny. In the words "gif thegen getheah thæt be wearth to eorle," &c., the use of the word eorl is most suspicious. This is not the eorl of antiquity—the Teutonic nobilis; it is the official eorl of the Danish and quasi-Danish periods. This anachronism betrays the real date of the production, and carries us to the times succeeding the reign of Ethelred II., when the disordered and transitional state of the country may have excited in the mind of the disquieted writer a fond aspiration which he clothed in the fanciful garb of his own wishes, rather than that of the gloomy reality which he saw before him.
The use of the cræft, for a vessel, like the modern, is to be found in the Andreas (v. 500.), a composition probably of the eleventh century.
The conclusion points to troubled and late times of the Anglo-Saxon rule, when the church missed the reverence which had been paid to it in periods of peace and prosperity.
I have said enough to show that this document cannot rank in accuracy or truthful value with the Rectitudines or the LL. of Hen. I.
One word more. What is the meaning of burh-geat? Burh I can understand; authorities abound for its use as expressing the manoir of the Anglo-Saxon thegn. The "geneates riht" (Rectitudines) is "bytlian and burh hegegian." The ceorls of Dyddanham were bound to dyke the hedge of their lords' burh ("Consuetudines in Dyddanhamme," Kemb, vol. iii. App. p. 450.): "And dicie gyrde burh heges."
H. C. C.