Abbildungen der Seite
PDF
EPUB

ROOM IN WHICH THE EARTH WAS WEIGHED.

The remarkable physical investigations by which certain philosophers have explained the Motion and ascertained the Density of the Earth, are glanced at in pp. 16 and 17 of the present volume ;* where is noticed the result obtained by Mr. Francis Baily, the astronomer, who, in 1838, within a small room, “contrived a pair of scales that enabled him approximately to weigh the vast sphere; when he ascertained that it had within itself some where about 1,256,195,670,000,000,000,000,000 tons of matter."

This memorable experiment was conducted by Mr. Baily in one of the rooms of his residence, No. 37 Tavistock Place. The house stands detached from any other building, in a large garden some distance from the street, the roadway of which is macadamised.t

The house consists of one story only, and the room in which Mr. Baily conducted his experiments is at the N.E. angle of the first floor, and has only one window. It will be seen by the accompanying view that in the roof of the house is a small observatory ; but the room we have to notice was preferred by Mr. Baily for the present experiments. Here he constructed apparatus differing in some respects from that with which Cavendish had made his celebrated experiment, which Mr. Baily repeated under new circumstances, and with all the improvements of modern artists. The great balls (or masses) were suspended from the ceiling by Cavendish ; but Mr. Baily supported them from the floor on a plank which turned on a pivot, and suspended the small balls from the ceiling, thus reversing the mode of operation. “Nothing," says Mr. Baily, “can exceed the ease, the steadiness, and the facility with which these large bodies are moved; and during the many thousand times they have turned backwards and forwards I have never observed the least deviation from the most perfect accuracy. At the final close of all the experiments the pivot turns as steadily, as freely, and as accurately, as at the commencement of the operations.” The small balls were also by Cavendish, suspended by a fine wire from the end of the torsion-rod, the motion of which was observed by means of a reflected image of the scale from a small mirror attached to the centre of the rod.

Such readers as are desirous of becoming acquainted with Mr. Baily's 2153 experiments and their results, are referred to vol. iv. of the Transactions of the Royal Astronomical Society, to the published Report of the inquiry, or to the Year-Book of Facts, 1843. In this room also Mr. Baily frequently made other experiments, recorded in the Philosophical Transactions for 1838. On these investigations we need not here enlarge, our object being in this place to record historically, by way of anecdote and illustration, the building in which the earth was weighed, and its bulk and figure calculated.

† The house was purchased by Mr. Baily of its former tenant, Mr. Benjamin Oakley, who attached to it a private theatre. The premises are in the rear of the residence of John Britton, the venerable antiquary, by whom the house, No. 17, at the south end of Burton Street, was purchased in 1820; and here he has produced a series of works upon the English Cathedrals and Architectural Antiquities, which have doubtless exercised considerable influence upon the encouragement of art by the wealthier classes, and have greatly benefited the professional man ; whilst the works themselves present an instance of strong natural abilities outmastering circumstances which is rarely paralleled. In Mr. Britton's Autobiography, which, in his 85th year, he is now presenting to the subscribers of a fund in testimony of his ability and integrity, he narrates some interesting characteristic traits in the life of his friend and neighbour, Mr. Francis Baily.

KING ARTHUR'S ROUND TABLE.
"And so great Arthur's seat ould Winchester prefers,
Whose ould round table yet she vaunteth to be hers."

Drayton's Polyolbion. Conspicuously upon the interior eastern wall of the County Hall at Winchester hangs the celebrated painted Table of King Arthur, the true

story of which has long been a disputed question with antiquaries ; but in 1845, when the Archæological Institute met at Winchester, a paper by Mr. E. Smirke was read upon this inquiry.

Tradition attributes the foundation of Winchester Castle to the renowned Prince Arthur; and the legendary bards affirm, that the large oaken table now shown as the chief curiosity of the place is the identical board around which that monarch and his celebrated knights assembled in the fortress he had founded : but the Exchequer Domesday shows that William I. erected the castle of Winchester in the situation in which exist its remains, including the County Hall, in which the Table bangs.

Mr. Smirke is not aware of any distinct reference to the Round Table before the reign of Henry VI. or Edward IV., when Hardyng, the poetic historian, alludes to the table of Arthur as “hanging yet” at Winches. ter; but this mention is not to be found in the earliest manuscript copy of Hardyng. Paulus Jovius informs us that the table was shown to the Emperor Charles V. on his visit to Winchester in 1522; and in the foreign accounts of Henry VIII. we find an entry of 661. 168. 11d. for the repair of the “aula regis infra castrum de Wynchestre et le round tabyll ibidem.” Again, the table is referred to by a Spanish writer who was present at the marriage of Philip and Mary, as the Round Table constructed by Merlin.

The Table, as we now see it, consists of a circle, divided into twentyfive green and white compartments radiating from the centre, which is a large double (Norman ?) rose. In the middle of the upper half of the circle, resting upon thé rose, and extending to the double edge, is a canopied niche, in which is painted a regal figure, bearing the orb and sword, and wearing the royal crown.

Around the centre rose is a circle inscribed with black-letter, except where it is broken by the base of the niche and the sitting king. There are also names inscribed in six of the white compartments, as well as in the circle around the compartments, of which however this circle is rather a continuation, in colour and form corresponding to the several divisions, each bearing a name. To what period these names are to be referred, Mr. Smirke leaves those to decide whose critical acquaintance with the cycle of the Round-Table romances will enable them to state the source from which the names are borrowed. But there is no doubt that, whatever retouching the table may have undergone (especially in the royal figure, which Mr. Smirke believes to have been repainted within the time of living memory), the form of the letters and general decorations of the table, eren if we had no extrinsic evidence, would indicate a date not later nor much earlier than the reign of Henry VIII.

The table is made of very stout oak plank, and is larger than the roof and the floors of the rooms in the Eddystone

hthouse, and considerably larger than the ground-plot of the parish church of St. Lawrence in the Isle of Wight.

THINGS

NOT GENERALLY KNOWN.

Marvels of the Heavens.

THE GREAT TRUTHS OF ASTRONOMY.

How difficult must these be for the uneducated to understand! “Tell a plain countryman,” says. Bishop Hall, that the sun, or some higher or lesser star, is much bigger than his cart-wheel, or, at least, so many scores bigger than the whole earth, he laughs thee to scorn, as affecting admiration with a learned untruth; yet the scholar, by the eye of reason, doth as plainly see and acknowledge this truth as that his hand is bigger than his pen."

ANCIENT IDEAS OF THE UNIVERSE. Far lower down than the times of astrology and alchemy was the age when this earth was thought the fixed centre of the universe and an extended plain, * and the heavenly dies glittering specks revolving round it; and when the great Aristotle taught that the heavenly bodies were bound fast in spheres which revolved with them round our earth—the bodies themselves being motionless—the first sphere being that in which the fixed stars are placed ; then the five planets; the sun; and, next to the earth, the moon : the earth itself being at rest, and the centre of the universe !-S. Warren, D.C.L.

MECHANICS OF ASTRONOMY. Our acquaintance with the sublime truths of Astronomy would have been as deep had Eastern philosophers never turned

* This notion is not yet apparently banished from among ourselves even. "I remember," says the present Astronomer Royal, “a man in my youth-my friend was in his inquiries an ingenious man, a sort of philosopher-who used to say he should like to go to the edge of the earth and look over.” “Airy's Lectures on Astronomy, p. 46, 2d edition, 1848.

B

their eyes to the realms of illimitable space, gazed enraptured on the canopy above, and watched the harmonious movements of the countless worlds which adorn the firmament they people. “The moment,” says Sir John Herschel, “ astronomy became a branch of mechanics, a science essentially experimental (that is to say, one in which any principle laid down can be subjected to immediate and decisive trial, and where the experience does not require to be waited for), its progress suddenly acquired a tenfold acceleration; nay, to such a degree, that it has been asserted, and we believe with truth, that were the results of all the observations from the earliest ages annihilated, leaving only those made in Greenwich Observatory during the single lifetime of Maskelyne, the whole of this most perfect of sciences might, from those data, and as to the objects included in them, be at once re-constructed, and appear precisely as it stood at their conclusion. The operation, indeed, of Arabian knowledge of astronomy in the early ages was, perhaps, principally to lend a plausibility to astrology, the observers of stars, like Columbus predicting the eclipse, had the power of astonishing when they prepared to delude.”

NATURE OF THE SUN. The most recent observations confirm the supposition that the Sun is a black, opaque body, with a luminous and incandescent atmosphere, through which the solar body is often seen in black spots, frequently of enormous dimensions. A single spot, seen with the naked eye, in the year 1843, was 77,000 miles in diameter. Sir John Herschel, in 1837, witnessed a cluster of spots including an area of 3,780,000 miles. The diameter of the sun is 770,800 geographical miles, or 112 times that of the earth ; its volume is 1,407,124 times that of the earth, and 600 times that of all the planets ; and its mass is 359,551 times greater than the earth's, and 738 times greater than all the planets.

THE SOLAR SYSTEM ILLUSTRATED. In order to convey to the mind of the reader a general impression of the relative magnitudes and distances of the parts of our system,“ choose," says Sir John Herschel," any well-levelled field or bowling-green. On it place a globe two feet in diameter, which will represent the sun ; Mercury will be represented by a grain of mustard-seed, on the circumference of a circle 164 feet in diameter for its orbit ; Venus, a pea, on a circle 284 feet in diameter; the earth also a pea, on a circle of 430 feet ; Mars, a rather large pin's head, on a circle of 654 feet ; Juno, Ceres, Vesta, and Pallas, grains of sand, in orbits of from 1000'to 1200 feet; Jupiter, a moderate-sized orange, in a circle

« ZurückWeiter »