A GENTLEMAN’S FASHION.
In the reign of Henry VII. sir Philip Calthrope, a Norfolk knight, sent as much cloth, of fine French tauney, as would make him a gown, to a tailor in Norwich. It happened one John Drakes, a shoemaker, coming into the shop, liked it so well, that he went and bought of the same as much for himself, enjoining the tailor to make it of the same fashion. The knight was informed of this, and therefore commanded the tailor to cut his gown as full of holes as his sheers could make. John Drakes’s was made “of the same fashion,” but he vowed he never would be of the gentleman’s fashion again.
Discoveries
OF THE
ANCIENTS AND MODERNS.
No. VII.
In the present stage of the inquiry will be adduced examples of the knowledge of the ancients, respecting the essential principles that “uphold the world.”
Gravity, Attraction—the Law of Squaring the Distances—Centripetal and Centrifugal Force.
The moderns, who imagine that they were the first to discover universal gravitation, have only trod in the paths of the ancients. It is true, that they have demonstrated the laws of gravitation, but this is all.
Besides universal gravitation, the ancients knew that the circular motion described by the planets in their courses, is the result of two moving forces combined—a rectilinear and a perpendicular; which, united together, form a curve. They knew also why these two contrary forces retain the planets in their orbs; and explained themselves, as the moderns do, excepting only the terms of “centripetal” and “centrifugal;” instead of which, however, they used what was altogether equivalent.
They also knew the inequality of the course of the planets, ascribing it to the variety of their weights reciprocally considered, and of their proportional distances; or, which is the same thing, in more modern terms, they knew the “law of the inverse ratio of the square of the distance from the centre of the revolution.”
Some have thought, that in Empedocles’s system the foundation of Newton’s was to be found; imagining, that under the name of “love,” he intended to intimate a law, or power, which separated the parts of matter, in order to join itself to them, and to which nothing was wanting but the name of attraction; and that by the term “discord,” he intended to describe another force, which obliged the same parts to recede from one another, and which Newton calls a repelling force.
The Pythagoreans and Platonics perceived the necessity of admitting the force of two powers, viz. projection and gravity, in order to account for the revolution of the planets. Timæus, speaking of the soul of the world, which animates all nature, says, that “God hath endowed it with two powers, which, in combination, act according to certain numeric proportions.”
Plato clearly asserts, that God had impressed upon the planets “a motion which was the most proper for them.” This could be nothing else than that perpendicular motion, which has a tendency to the centre of the universe, that is, gravity; and what coincides with it, a lateral impulse, rendering the whole circular.
Diogenes Laertius says, that at the beginning, the bodies of the universe were agitated tumultuously, and with a disorderly movement; but that God afterwards regulated their course, by laws natural and proportional.
Anaxagoras being asked what it was that retained the heavenly bodies in their orbit, notwithstanding their gravity, remarkably answered, that “the rapidity of their course preserved them in their stations; and that should the celerity of their motions abate, the equilibrium of the world being broken, the whole machine would fall to ruin.”
Plutarch, who knew almost all the shining truths of astronomy, in explaining what it was that made bodies tend towards the earth, attributes it to “a reciprocal attraction, whereby all terrestrial bodies have this tendency, and which collects into one the parts constituting the sun and moon, and retains them in their spheres.” He afterwards applies these particular phenomena to others more general; and, from what happens in our globe, deduces, according to the same principle, whatever must thence happen respectively in each celestial body; and then considers them in their relative connections one towards another. He illustrates this general relationship and connection, by instancing what happens to our moon in its revolution round the earth, comparing it to “a stone in a sling, which is impressed by two powers at once;” that of projection, which would carry it away, were it not retained by the embrace of the sling; which, like the central force, keeps it from wandering, whilst the combination of the two moves it in a circle. In another place, he speaks “of an inherent power in bodies, that is, in the earth, and other planets, of attracting to themselves whatever is within their reach.” In these two passages, there is a plain reference to the centripetal force, which binds the planets to their proper, or common centres; and to the centrifugal, which makes them roll in circles at a distance.
The ancients, then, attribute to the celestial bodies a tendency towards one common centre, and a reciprocal attractive power. It appears also, that they knew, as well as the moderns, that the cause of gravitation, that attracted all things, did not reside solely in the centre of the earth. Their ideas were even more philosophic; for they taught, that “this power was diffused through every particle of the terrestrial globe, and compounded of the various energy residing in each.”
It remains to inquire, whether they knew the law by which gravity acts upon the celestial bodies, that it was in an inverse proportion of their quantity of matter, and the square of their distance. Certainly they were not ignorant, that the planets in their courses observed a constant and invariable proportion; though some sought for it in the difference of the quantity of matter contained in the masses, of which the planets were composed; and others, in the difference of their distances. Lucretius, after Democritus and Aristotle, thought that “the gravity of bodies was in proportion to the quantity of matter of which they were composed.” It is true, that the penetration and sagacity of a Newton, a Gregory, and a Maclaurin, were requisite to perceive and discover, in the few fragments of the ancients now remaining, the inverse law respecting the squares of the distances, a doctrine which Pythagoras had taught; but they acknowledge that it was contained in those writings; and they avail themselves of the authority of Pythagoras, to give weight to their system.
Plutarch, of all the philosophers who have spoken of Pythagoras, had a better opportunity of entering into the ideas of that great man, and has explained them better than any one besides. Pliny, Macrobius, and Censorinus, have also spoken of the harmony which Pythagoras observed to reign in the course of the planets; but Plutarch makes him say, that it is probable that the bodies of the planets, their distances, the intervals between their spheres, the celerity of their courses and revolutions, are not only proportionable among themselves, but to the whole of the universe. Dr. Gregory declares it to be evident, that Pythagoras understood, that the gravitation of the planets towards the sun was in a reciprocal ratio of their distance from that luminary; and that illustrious modern, followed herein by Maclaurin, makes that ancient philosopher speak thus:—
“A musical string, says Pythagoras, yields the very same tone with any other of twice its length, because the tension of the latter, or the force whereby it is extended, is quadruple to that of the former; and the gravity of one planet is quadruple to that of any other, which is at double the distance. In general, to bring a musical string into unison with one of the same kind, shorter than itself, its tension ought to be increased in proportion as the square of its length exceeds that of the other; and that the gravity of any planet may become equal to that of any other nearer the sun, it ought to be increased in proportion as the square of its distance exceeds that of the other. If, therefore, we should suppose musical strings stretched from the sun to each of the planets, it would be necessary, in order to bring them all to unison, to augment or diminish their tensions, in the very same proportion as would be requisite to render the planets themselves equal in gravity. This, in all likelihood, gave foundation for the reports, that Pythagoras drew his doctrine of harmony from the spheres.”[353]
Galileo duly honours Plato, by acknowledging that he is indebted to him for his first idea of the method of determining, how the different degrees of velocity ought to produce that uniformity of motion discernible in the revolutions of the heavenly bodies. His account is, that “Plato being of opinion that no movable thing could pass from a state of rest to any determinate degree of velocity, so as perpetually and equably to remain in it, without first passing through all the inferior degrees of celerity or retardation; he thence concludes, that God, after having created the celestial bodies, determining to assign to each a particular degree of celerity, in which they should always move, impressed upon them, when he drew them from a state of rest, such a force as made them run through their assigned spaces, in that natural and direct way wherein we see the bodies around us pass from rest into motion, by a continual and successive acceleration. And he adds, that having brought them to that degree of motion, wherein he intended they should perpetually remain, he afterwards changed the perpendicular into a circulary direction, that being the only course that can preserve itself uniform, and make a body without ceasing keep at an equal distance from its proper centre.”
This acknowledgment of Galileo is remarkable. It is a homage to antiquity from an inventive genius, who least of any, owes his eminence to the aid of the ancients. It is the disposition of noble minds to arrogate to themselves as little as possible any merit, but what they have the utmost claim to; and thus Galileo and Newton, the greatest of modern philosophers, set an example, which will never be imitated but by men of distinguished greatness.
[353] Gregorii Astronomiæ Elementa; and Maclaurin’s Systems of the Philosophers, in a discourse prefixed to his philosophy of Newton, p. 32. Wallis, vol. iii. p. 138 and 150.
AVON MILL, WILTS.
The Gleaning or Leasing Cake.
To the Editor.
Sir,—It may not be deemed an intrusion to inform your readers, that when Avon Mill was devoted to the grinding of corn it was very centrally situated for the convenience of the poor gleaners. This mill, then kept by a family of the name of Tanner, (the sons were renowned swimmers,) had also much business with the neighbouring farmers and maltsters. At the time, dame Tanner, one of the best-hearted women then living, had a custom of her own, (perhaps to discharge the dictates of a good conscience for the double toll taken by the millers.) She made after the harvest-season a cake, somewhat after the manner of the Jews’ passover cakes, given to their Gentile friends, which she called the “Gleaning cake,” and gave it to every poor person that brought gleaned corn to be ground at the mill. A few years after her death the mill was purchased (I think a chancery suit was pending) for a clothing manufactory, (one pair of stones only being kept,) which it still remains. When the shearing machines were here first introduced to cut and dress cloth by water, detachments of troops were nightly stationed in the lanes and mill to prevent large bodies of the shearmen, then out of employ, from setting fire to the premises. At subsequent periods much business has been done here in the manufacture of superfine broadcloth, but owing to the fluctuation of trade Avon Mill has not generally done half the work of its water power.
A neighbouring mill, once also a great corn mill, at Christian Malford, but which is now a spacious edifice, has shared nearly the same fate and devotedness. The water-wheels being partly undershot on this beautiful river, the water in autumn is often insufficient to the demand; but when after heavy rains the floods are out, the meadows present a sheet of blue expanse truly picturesque, and the bridges, by the depth and rapidity of the current near the mills, are nearly impassable. Many peasants returning home, and farmers riding from market, have by their adventure missed their way and been drowned.
A “pretty considerable number” of ghost stories are floating in the memories of the aged cottagers, of persons appearing after death on the Avon and its banks in this part of the country.
I am, sir,
Yours respectfully,
An Old Correspondent.
T——n, T——e,
August 21, 1827.