Old and New London, A Narrative of its History, its People and its Places.Illustrated with Numerous Engravings from the Most Authentic Sources. vol 6
Greenwich (continued).--The Park, The Royal Observatory, &c.
Greenwich (continued).--The Park, The Royal Observatory, &c.
It was, no doubt, the peculiar charm of this unrivalled prospect that made Greenwich for so many ages the favourite seat of our Tudor monarchs, to whose purposes it was excellently adapted, both for its vicinity to the metropolis and its commanding situation. But far different must have been the scene when (we are told) Henry VIII., in the year of his reign, on a fine May-day morning, with Queen Katharine his wife, accompanied also by many lords and ladies, rode a-Maying from Greenwich to the high ground of Shooter's Hill, where, as they passed by the way, they espied a company of tall yeomen all in green, with hoods, and with bows and arrows, to the number of . Since that day, alterations have taken place which must astonish even the last generation, large tracts of land, which then were either marketgardens or pastures for cattle, being now converted into docks or built over as streets.
writes Mr. T. Miller, in his
he suggests, with a vein of dry humour,
This, we may add, is a very pretty and poetical picture, but none the less true for all that.
[extra_illustrations.6.207.1] is the same as that previously mentioned as having been enclosed by Humphrey, Duke of Gloucester, in , by licence of King Henry VI. It contains nearly acres, and was
| walled round by James I. Here, as in Kensington Gardens, we find the umbrageous trees that were planted by Gilpin and Le Notre, and the gardeners of William III. It was chiefly laid out by Le Notre, about the same time as , by order of Charles II., who, it is recorded, watched with great eagerness the work of laying out this park. As early as the spring of , Pepys records that, |
here referred to was a tower erected by Duke Humphrey, on the site now occupied by the Observatory. Traces of Le Notre's
or terraces are still observable in the hill-side leading to it. Castle Hill, it would seem, was at time used as a
or target for military practice; at all events, Evelyn, in his
under date of , writes:
Of the time when the chief avenues were planted we get the exact date from the following entry in Evelyn's
where, under date of , he writes:
Now, however, except in the remains of some of the avenues, there are not very strong traces of the stiff and formal style of Le Notre left, as it is not on a beautifully-varied surface like this that straight walks and regular lines of trees are at all tolerable. The natural advantages of this park are certainly superior to those of any in the immediate vicinity of the metropolis.
says the author of
The chestnuts in Blackheath Avenue have passed maturity, and every year seems to be telling on their strength. Many of them have magnificent trunks, and a few of them exceed eighteen feet in girth; some of the chestnuts, too, have attained a noble growth. The oaks are comparatively few, but among them are some of the largest trees in the park. The whole extent of the park is greatly varied in surface, and hence its great charm. As Mr. James Thorne, in his
--that particular spot rendered famous by [extra_illustrations.6.207.3] , in his
in the familiar lines-
| is so called from there having been but tree on its summit; this tree, however, has long been greatly decayed, and others were, some years ago, planted near it. It was in former times called |
About the year it was proposed to raise a monumental trophy, in honour of the battle of Trafalgar, on the summit of Castle Hill, near the Observatory, but the project was relinquished for want of sufficient funds. This trophy was intended to have been elevated to a height of about feet, and, had it been carried into effect, would have been a landmark to vessels on the river, and a conspicuous object to the country for miles around. On the brow of the hill, in the park, and about the front of the Observatory, you would see, till very recently, the old pensioners with their telescopes and glasses of every colour. Some of these heroes, who had served under Jervis and Nelson, had lost a leg or an arm, or possibly both; and yet they went about the park with their
as happy, to all appearance at least, as the credulous cockneys whom they delighted to cram with all sorts of improbable yarns about battles fought by
in which they shot their cannonballs to the very longest of all possible ranges. This hill was a favourite place, not only for the Greenwich pensioners, but for gipsies and fortunetellers.
writes the ingenious Arthur Young, in a somewhat poetic strain,
The same view is thus described by Thomas Miller, in his work above quoted:--
We have already mentioned that this park was a favourite lounge for Dr. Johnson during the time he was lodging in Greenwich.
[extra_illustrations.6.208.1] , was the scene of every variety of joyous hilarity, from
and other games, to the exciting rush and tumble down the hill. The frolic and mirth everywhere visible here on these occasions is well described in the following , in :--
Groups of nurserymaids and children are familiar features in the modern aspect of Greenwich Park. The latter flit, climb, and leap over every broken hillock, slide into every green dell, swing, toss, and tumble round and upon each sinewy tree, as if they were the legitimate possessors of the park, and lived entirely upon gingerbread, oranges, nuts, and lemonade-viands which, it seems proper to believe, are indispensable to the real enjoyment of these shady avenues.
In Albert Smith's description of Greenwich Fair, from which we have quoted largely in the preceding chapter, part of the scene is laid in the park.
writes the author of ,
About June the park may be seen in all its bloom and beauty--the fine old hawthorns are then still in full blossom, and the hundreds of gigantic elms and chestnuts are hung in their richest array of summer green, whilst here and there the deer cross and re-cross the shady avenues, or, crouching amid what is called the
lie half buried in the fan-like fern. The hill and the plain below, and, in fact, the whole greensward round, are clothed in their holiday attire, the female part of the community lighting up the scene by the varied hues of their dress. At every few yards you meet with a new group of pleasure-seekers, whilst the long avenue which leads up to Blackheath is continuous stream of merry-looking people.
On the south-west side of the park, and facing Blackheath, stands the Ranger's Lodge, a brickbuilt mansion, formerly the residence of Philip, Earl of Chesterfield, who purchased it about the middle of the last century, and considerably enlarged and improved it. In his
the earl calls it
but it was commonly known as
|, and his connection with it is still kept in remembrance by the name of |
which has been given to the shady pathway running along under the park wall from the top of Croom's Hill. In the house became the residence of the Duchess of Brunswick, sister of George III., and was thereupon called Brunswick House. The duchess came hither in consequence of her daughter, Caroline, Princess of Wales, having had the adjoining mansion, Montagu House, assigned her as a residence when appointed Ranger of Greenwich Park, in the year . On her death the house was purchased by the Crown, and appropriated as the residence of the Ranger. Here the Princess Sophia resided from till her death. In more recent times it was the residence of Prince Arthur, now Duke of Connaught, whilst studying for the Engineers.
Montagu House, which stood immediately to the south of the Ranger's Lodge, owed its name to having belonged to the Duke of Montagu, who bought it in . Whilst it was the residence of the Princess of Wales, the grounds attached to it were enlarged by enclosing a portion of the park, called the
This now forms
|a part of the Ranger's Lodge. Montagu House was pulled down in , but the name is preserved in Montagu Corner, at the end of Chesterfield Walk. At the junction of Chesterfield Walk and Croom's Hill is a large mansion, once the seat of General Wolfe, and the occasional residence of his son, the hero of Quebec, whose remains were brought hither before they were buried in Greenwich Church. The house was afterwards the residence of Lord Lyttelton.|
On the south-west side of the park, above the summit of the hill, and in the rear of the house above mentioned, are several barrows, or tumuli, which, it has been conjectured, may have been the burial-places of the Danes during their encampment on Blackheath. Some of them were opened towards the end of the last century, when there were discovered in them spear-heads, human bones and hair, knives, fragments of woollen cloth, and other articles.
It is time now that we made our way once more to the summit of the hill whereon stands the Observatory, a spot which Tickell calls-
The Observatory, as we have mentioned above, occupies the site of the tower, commonly called
which was built by Duke Humphrey. This tower was repaired, in , by Henry VIII., and was used sometimes as a habitation for the younger branches of the royal family, sometimes as a prison, occasionally as a place of defence, and at other times as a residence for a favourite mistress.
(Henry VIII.), writes Puttenham, in his
We do not know what was the result of the king's running, or what was its immediate object. In , Mary of York, daughter of Edward IV., died in this tower. In the reign of Queen Elizabeth it was called
and the Earl of Leicester was confined in it, when he had incurred the Queen's displeasure by marrying the Countess of Essex. Henry Howard, Earl of Northampton, Lord Privy Seal, and the founder of Norfolk College, in East Greenwich, had a grant of this tower from James I.; he is said to have enlarged and beautified the building, and to have made it his principal residence. In , Elizabeth, Countess of Suffolk, died here. years later, being then called
it was considered of so much importance as a place of defence, that the Parliament took immediate measures to secure it against the King.
After the Restoration, M. de St. Pierre, a Frenchman, who came to London about the year , having applied to King Charles II. to be rewarded for his discovery of a method of finding the longitude by the moon's distance from a star, a commission was appointed to investigate his pretensions. Lord Brouncker, President of the then young Royal Society, Sir Christopher Wren, the Surveyor-General, and City architect--for nearly half London was then in ruins-Sir Jonas Moore, Master of Ordnance, and many other
about the town and court, composed the board,
which power they exercised by the addition of a certain Mr. John Flamsteed, who was introduced by Sir Jonas Moore, and whose name, from that day to this, has been associated with this hill.
Flamsteed, who was born at Denby, Derbyshire, in , had already distinguished himself as an astronomer; for, previous to the erection of this Observatory, he had made sundry observations of the heavenly bodies in a turret of the building called the
in the , which turret is still called the
On hearing the Frenchman's proposals, Flamsteed at once pointed out their impracticability, in consequence of the imperfect state of the tables representing the motions of the moon, and the inaccuracies of the existing catalogues of the fixed stars. He likewise set to work on some observations of his own, which at once frustrated the schemes of St. Pierre, who was no more heard of. The commissioners thereupon communicated the results of Flamsteed's observations to the king;
Sir Jonas Moore --accordingly conveys to the young astronomer the royal warrant appointing him
and enjoining him
For this important service he was to receive the munificent stipend of per annum!
The next thing to be settled was the site of the [extra_illustrations.6.213.1] , and, upon the advice of Sir Christopher Wren, Greenwich Hill was chosen. The old tower was accordingly ordered to be demolished; and the stone of the new building was laid in . In exactly a year from that date the edifice was handed over to Flamsteed, and from him it acquired the name of Flamsteed House. In the following month he began his observations, with a sextant of feet radius, contrived by himself, and such other instruments as were then known. Notwithstanding his scanty income, and the difficulty he experienced in obtaining such instruments as he required, Flamsteed's zeal overcame all obstacles, and during his lifetime the Observatory rose to that rank which it has ever since maintained among similar institutions.
It may be worth while to consider here what was the state of practical astronomy at the time when Flamsteed commenced his labours. Neither telescopes nor clocks had yet been introduced into observatories; the star catalogue of Tycho Brahe was derived from observations made with instruments furnished with plain sights; and this, together with the Rudolphine tables of the sun, moon, and planets then known (which were constructed from elements quite as rough), were the only materials existing for the use of the theoretical astronomer. Flamsteed, who knew what was needed, and who had a much better idea than any man of his time of the means necessary for producing comparatively good observations, set about his task with vigour. He was totally unprovided with instruments at the public expense, but he brought with him to the Observatory an iron sextant of feet radius, and clocks, given him by Sir Jonas Moore, together with a quadrant of feet radius, and telescopes, which he had brought with him from Denby. With these instruments he worked till the year , when he borrowed from the Royal Society a quadrant of inches, which, however, he was allowed to retain only a short time. It must be borne in mind that the advantages of the system of meridian observations were unknown, or nearly so, at this time. The sextant was employed to measure the distances of an object to be observed from some standard stars, or stars whose places were supposed to be better known, and a laborious calculation was necessary to deduce the resulting place of the body in every instance. This gave, however, no means of fixing the place of the body with respect to the equinox; and Flamsteed, finding the absolute necessity for an instrument fixed in the plane of the meridian, applied to the Government. He was not denied; but being wearied with repeated promises which were never kept, he at length resolved to make a
at his own expense, and this instrument was finally erected, and divided with his own hands in . It was, however, a failure; and his observations were continued for several years longer with the sextant. The minor obstructions and vexations to which Flamsteed was subjected we have not space to mention. It is sufficient to say that, during the whole time that he officiated as Astronomer-Royal (nearly half a century from his appointment), he was not supplied by the Government with a single instrument. The only assistance he was furnished with was that of
to assist him with the sextant; the other assistants and computers he provided at his own expense.
In Flamsteed was presented to the living of Burstow, in Surrey; having been from his early life desirous of devoting himself to the duties of the ministry.
he says, in his
His father died a few years afterwards; and these circumstances improving his estate, he determined to construct a new
stronger than the former; and this instrument, famous as really commencing a new era in observing, was constructed by Mr. Abraham Sharp, his friend and assistant, at an expense of , no portion of which was reimbursed to him by the Government. All Flamsteed's former observations were of little value; no fundamental point of astronomy was settled by them; and they merely served for forming a preliminary or observing catalogue of objects to be well observed with his new instrument. From the date of the use of this instrument, , the useful labours of Flamsteed commenced; every observation made after this was permanently useful, and could be applied to determine some important point. With this instrument, after verifying its position and determining its adjustment, he set about the determination of those cardinal points in astronomy, the position of the equinox, the obliquity of the ecliptic, and other fundamentals, without which the correct positions
| of the fixed stars and the planetary bodies could never be ascertained. His methods and processes are explained by himself in the |
a work in folio volumes, the of which contains his catalogue of stars, carried down to the year . His work still holds a high place in the history of astronomy.
What instruments Flamsteed had to work with, then, we are assured he had to provide and pay for himself; and in order to do this, he was compelled to turn
Government had already imposed upon him the education, monthly, of boys from , as if his tedious watches by night, and his laborious calculations by day, were not sufficient return for his paltry pittance, which was reduced by a tax to a year. He thereupon, as we have said, gave lessons in his favourite science, and obtained for pupils sundry dukes and lords, with many captains of vessels and East India servants, thus augmenting his pecuniary means.
Flamsteed appears soon to have made many friends, among whom was the venerable John Evelyn, who, under date of , makes this entry in his
Evelyn, we need scarcely state, should have written
But he is not the only person who has made this confusion. For it is a fact worthy of being placed on record that seldom a week passes without ladies driving from London in their carriages to the doors of the Observatory, and inquiring if they can have their
cast, evidently showing that they do not know the difference between astrology and astronomy. It is to be feared that on this subject great superstition prevails, even among the
classes; and that whilst fortune-tellers, who practise on poor servant-girls, are pounced upon by the police, some of the professors of the secret science, called
are making fortunes, by charging a guinea for every consultation, or ! But we must now return to our subject. On the , John Evelyn writes :--
Again, some years later, namely, on the , we meet with this entry:--
About this time, or shortly after, Flamsteed became friendly with Sir Isaac Newton, who was engaged in investigating the irregularities of the moon's motions, for the confirmation of his theory of universal gravitation, and who required accurate observations of the moon for comparison of fact with fancy. No but Flamsteed could supply these, and from time to time Newton visited him in order to obtain them. But this friendship was not of long duration. A difference arose between them, on account of an innocent statement by Flamsteed, to the effect that he had furnished Newton with a mass of lunar observations to assist him in his investigations, getting into print. Some angry correspondence ensued, and the dispute, after slumbering for a few years, broke out into a lamentable quarrel. In course of time, Flamsteed's valuable store of observations, extending over the period of years which he had then passed as Astronomer-Royal, were prepared for publication. Prince George of Denmark, consort of Queen Anne, undertook to bear the expense of printing; and a committee, with Sir C. Wren and Newton among the number, was appointed to examine the manuscript, and see the work through the press. During its progress, the latent quarrel between Flamsteed and Newton broke out afresh, and arrived at its culmination, turning upon the difference that existed between Flamsteed and the referees concerning the plan of publication of his work. The book,
was at length published, and so much did it annoy its author, that when, a few years after, the undistributed copies, about -fourths of the entire impression, were placed in his hands, he at once committed the whole of them to the flames,
He then resolved to publish a complete edition of his observations on his own plan, and at his own expense. It was to appear in volumes; but on the completion of the volume, his life's weary toil was brought to a close, on the last day of the year .
Flamsteed was succeeded by Dr. Halley, an astronomer also of great eminence, who, finding upon his appointment that the Observatory was destitute both of furniture and instruments (Flamsteed's having been removed by his executors as his personal property), furnished it anew, and fixed a transit instrument. Its introduction is stated to
| have been the most important step that had been made. It is the most simple and effective of all astronomical instruments; and up to the present time, the only changes that have been made in the means for observing the right ascensions of the heavenly bodies, are those which secure to it the utmost possible stability and accuracy of workmanship and adjustment. With it alone Halley continued to make observations of the moon till the year , when an -foot mural quadrant, made by Graham, was set up at the public expense. Of the small salary received by Dr. Halley for his important duties the following anecdote has been related :--On the accession of George II., the queen consort, Caroline, made a visit to the Royal Observatory. Being pleased with everything she saw, and understanding the smallness of the astronomer's salary ( per annum), her Majesty very graciously said she would speak to the king to have it augmented, to which Dr. Halley replied in alarm, |
However, understanding that the doctor had formerly served the Crown as a captain in the navy, the queen soon after was able to obtain a grant of his half-pay for that commission, which he accordingly enjoyed from that time up to the end of his life.
Halley died in , and his successor was [extra_illustrations.6.215.1] . This eminent astronomer made a noble series of observations, extending over the years during which he held the post. In many valuable additions were made to the stock of instruments. Bradley died in the year , and was succeeded by Dr. Bliss, who lived only till . The office next devolved upon [extra_illustrations.6.215.2] , who for nearly years performed the duties with wonderful assiduity; scarcely ever leaving the Observatory, except on some important scientific business, and making all the laborious and delicate observations himself, although he had the co-operation of a skilful assistant. He suggested the publication of the , a work of indispensable use to seamen, of which he edited no less than volumes. At his death he left large folio volumes of printed observations as the result of the patient labour of his life. In an order was issued by George III. that the observations made at Greenwich should be published, under the superintendence of the Royal Society; they have, accordingly, since been published annually by that learned body. The principal addition made to the Observatory during Maskelyne's directorship was the building of the
room, contiguous to and east of the transit-room. Maskelyne died in , leaving behind him an enviable reputation. The observations made by this astronomer during his years' residence at Greenwich were so valuable, that it has been remarked of him by his biographer, that if the whole materials of science should be lost except the volume of observations left by him, they would suffice to reconstruct the edifice of modern astronomy. He was succeeded by Mr. John Pond, who held office till the year , when ill health compelled him to resign; he died in the following year, and was buried at Lee, in the same tomb with his predecessor, Dr. Halley. During Mr. Pond's directorship the Observatory acquired that organisation which it has since retained, and which was necessary to enable it to meet the demand made upon it by the requirements of modern science. On his entrance upon his duties he began, like his predecessors, with assistant; but on his representations and urgent entreaties for increase of the establishment, he finally obtained assistants; and this amount of force for the astronomical department of the Observatory has been continued with some modifications to the present time. Pond was peculiarly skilful in the theory of astronomical instruments, and in the interpretation of the results afforded by them. Sir George Airy, in of his official reports, states that he regards him as the
On the resignation of Mr. Pond, Mr. George Biddell Airy, then Director of the Observatory at Cambridge, was appointed to the vacant office.
writes Mr. Carpenter, in the (),
Greenwich Observatory has little to recommend it as a building. It was never intended for show, but for work. It was constructed in haste, chiefly with the materials of the old tower, and some spare bricks that lay available at Tilbury Fort, The admissions to the building are strictly limited to such individuals as are most likely to be benefited by visiting it, and idling sightseers are carefully
|excluded. A card is kept in the porter's lodge, which explains that the privilege of visiting the Observatory is of necessity very limited, those officially privileged being officers of the Royal Navy and gentlemen officially connected with the Admiralty; other visitors are required to be furnished with an introduction from some person of scientific distinction.|
A few objects arrest attention outside the walls of the edifice. For instance, the hour electric clock, supposed by the uninitiated to be kept going by the sun; the public barometer, with its indices, showing the highest and lowest readings during the past few hours; the little windmill like a child's toy on the roof; and the high pole with a light at the top, conjectured to be a beacon to show the longitude at sea. other external object must not be overlooked: this is an iron plate fixed against the wall, with a number of brass plugs and pins projecting from it, with the inscriptions,
&c., over them.
says Mr. Carpenter, in an article in the , from which we have already quoted,
On passing inside the gate, the object that presents itself is a range of low buildings immediately to the left, railed off from the more common portions of the court. The old-fashioned yet rather
| picturesque gables and roughly-tiled roofs of these buildings, and their general humble aspect, give no evidence of their use, except what may be gathered from the slits, closed by shutters, which in places intersect them, and the domes that flank them at their eastern and south-western extremities; yet in these unpretending rooms not only are all the observations made which give its fame to the establishment, but the reduction of them is also performed there, and they are rendered fit for the immediate use of the astronomer. The door immediately opposite, as we cross the court, is that of the Astronomer-Royal's residence, all the apartments of which are on the groundfloor, and situated on either side of a long gallery running nearly east and west. On the wall of the building, near this doorway, is a slab containing the original inscription set up at the erection of the Observatory; it is as follows:--
A doorway near the eastern end of the range of buildings leads into the transit-circle room, of the principal observing-rooms of the establishment. To the reader not familiar with the instruments and processes of astronomy it may be desirable to explain that the transit-instrument is a telescope which is supposed theoretically to describe the plane of the meridian. For this special purpose it is furnished with axes, terminating in wellpolished equal cylindrical pivots; and these pivots being placed in bearings sunk in the stone piers shaped like the letter Y (technically called |
), the instrument is capable of revolving freely. [extra_illustrations.6.217.1]
We may here remark that the principal duty of the practical astronomer is the determination of right ascensions and polar distances.
says Mr. Carpenter,
Upon the same wall on which hangs Halley's primitive instrument, are suspended or other transit instruments, which in their time have doubtless rendered good service to astronomical science. These are the instruments introduced by Dr. Bradley, and also Troughton's noble instrument, used by Maskelyne and Pond, and by the present Astronomer-Royal up to the year , when it was dismounted to give place to the gigantic
now in use. This lastmentioned instrument is, in fact, a combination of instruments, seeing that it has also superseded the
by means of which a star or planet's polar distance was formerly ascertained. This instrument is feet in length, and its largest glass is inches in diameter. Attached to the telescope is the circle which answers to the
around its circumference is a narrow band of silver, upon which are engraved those divisions representing degrees of angular measurement, of which the whole circle contains . These degrees are further subdivided into smaller intervals of minutes, and the intermediate minutes and seconds, and decimals of a , are what is technically termed
by means of micrometers, of which are used, and their mean taken, to eliminate errors of observation, &c. These micrometers are affixed to of the piers supporting the instrument, the pier itself being perforated to allow the divisions to be seen through it. Another circle attached to the telescope is a clamping circle, for the purpose of fixing the instrument rigidly during an observation. Counterpoises in various parts, apparatus for raising the instrument, and other appliances necessary for purposes of adjustment, make up the other details of the
in front of which stands the
which is its indispensable accessory.
We have arrived, let us suppose, a little before noon; the sun is about to cross the meridian, and an observation is to be made. Shutters in the roof are thrown open, the great telescope is swung up and fixed in position, and an observer seats himself at the lower end of it. Peeping through the instrument, all that could be seen by an
observer would be a number of vertical lines, technically called
but in reality so many pieces of cobweb, as mentioned above, stretched across the field of observation at irregular distances. The centre is the celebrated meridian of Greenwich, or, at all events, it represents it, and it is curious to reflect that from this centre line ships of all civilised nations, and in all parts of the known world, are reckoning their distances. What the regular observer has to do is to record the precise instant at which the sun's edge, or
as astronomers call it, passes that central
In any single observation, however, he may be a little at fault, and for the sake of greater accuracy, therefore, he notes the instant at which it passes over all the
and then strikes an average between them. Slowly the sun creeps up to the line, and the observer lightly taps a little spring attached to the telescope. The
is reached, and again the spring is tapped, and so on throughout the whole or webs employed in the observation. This spring is connected with a telegraphic wire extending to a
in a distant part of the building, which consists of a cylinder, around which a sheet of white paper has been strained. The cylinder itself is revolved by the pendulum of an electric clock, which, instead
| of oscillating backwards and forwards, swings round in a circle, thus producing a motion perfectly uniform and unbroken. A little steel point, which is travelling over the surface of the paper, is in electric communication with the spring attached to the great telescope; |
observes a writer in
other object in the apartment containing the
should not be passed unnoticed; it is the identical instrument with which Bradley made his important discovery of the aberration of light.
The next important instrument is the altitude and azimuth, or, as it is termed, for shortness, the
which is located in the south dome of the Observatory buildings. This instrument was erected in , for the sole purpose of observing the moon. Next to the sun, the most important of the heavenly bodies is the moon, for, independently of her use in regulating the division of the year into months, and creating the tides of the ocean, she is indispensable to nautical science, as her motions afford the only means of accurately determining the longitude at sea. The Observatory was originally founded for observations necessary to bring to perfection the lunar tables, and for the improvement of nautical astronomy. The observation of the moon in every part of her orbit has always been, therefore, an object of -rate importance. To effect this, meridian observations have been regularly made in fixed observatories, as alone giving results of the requisite excellence. But, since the moon is invisible at her meridian passage for nearly - of her orbit --viz., for about days, on the average, before conjunction, and for days after it-and since also a great many observations in each lunation are necessarily lost by cloudy weather, it became a great desideratum to supply, if possible, by extrameridional observations, these defects. The altitude and azimuthal instrument was evidently the kind of instrument that must be employed for this purpose, because, its axes being horizontal and the other vertical, the parts of the instrument are equally affected by gravity in every position, and the only thing wanted to produce observations which should rival those made with the transitinstrument and mural-circle, would be sufficient firmness. To secure this the Astronomer-Royal adopted as his principles of construction,
The instrument is, therefore, as the visitor would at once see, of unusual weight and solidity. of the vertical cheeks that are on each side of the telescope carries, in cast of metal, the microscopes for reading the vertical circle, and the supports of the levels parallel to the plane of that circle. The lower piece connecting these cheeks, or the base plate, carries in cast the microscopes for reading the horizontal or azimuthal circle, and supports levels parallel to the horizontal axis; and the upper connecting piece carries other levels similarly situated on the upper pivot. These pieces are most firmly connected with the side vertical cheeks by means of planed surfaces and screw bolts. The vertical circle was made in casts of metal-viz., the cylindrical part, the spokes and pivots on side, the object-end and the eye-end of the telescope were made in cast; and in the other cast are included the spokes and pivot on the other side. Thus the whole of the essential parts of the instrument, with regard to firmness, were made in casts of metal. The weight of these parts is about hundredweight.
Some idea of the importance of the Greenwich lunar observations may be inferred from the circumstance that, during the century ending with the year , Greenwich contributed nearly observations of the moon towards the improvement and perfection of the vexatious lunar theory; all reduced under the direction of Sir G. B. Airy, and rendered immediately available for the investigations of the physical astronomer, the lunar tables now in use being chiefly based upon these observations. Since the introduction of the
the number of observations of the moon formerly made here in the course of each year has been about doubled, and, as a natural consequence, the value of the Greenwich lunar observations has been largely increased.
It may be asked by some of our readers, how are the Greenwich observations of the moon connected with navigation? A few lines by the author quoted above may be given as a reply.
We will now pass on to the interior of the very large dome, or rather drum, that caps the southeastern extremity of the Observatory. In it is a magnificent specimen of the class of instrument known as the
The dome itself, which has an opening closed by curved shutters, sliding upwards and downwards, moves round with sufficient ease by means of a toothed wheel and rack, the manual power being applied at the ends of long radial bars.
The author whom we have already quoted remarks that,
We have now seen all the more prominent features of the astronomical department of Greenwich Observatory, though there yet remain many other objects of the utmost scientific interestsuch as rain-gauges, hygrometers, anemometers, and thermometers, placed in all kinds of positions, and under all kinds of conditions. In room is a very large number of Government chronometers, required for the use of ships; while in a building apart from the Astronomical Observatory, is a Magnetic Observatory, established about the year , for the purpose of ascertaining and recording the various phenomena of the magnetic currents of the earth.
writes Mr. J. Carpenter,
Nothing, perhaps, throughout the Observatory is calculated to strike the visitor with greater astonishment than the motor clock above referred to. There is nothing very remarkable in its appearance, but the work it accomplishes renders it, perhaps, the most wonderful clock in the world, and certainly the most important in England. The writer above quoted continues--
It is no longer, therefore,
but Greenwich Observatory, which regulates the time of all the clocks and watches in London. The authorities have granted the special use of a system of electric wires to the inventors of a method for synchronising clocks. The arrangements recently completed bring the Greenwich Observatory into direct communication with the establishment at of Messrs. Barraud and Lund, the inventors of an apparatus by means of which existing clocks can be automatically
The mechanism is of the simplest kind; it interferes in no way with the works of a clock, and can be applied to any timepiece in or out of doors. Any number of clocks, varying in size and calibre, can, upon receipt of time-signal, be simultaneously set to accord with each other in accurately denoting Greenwich time. A very small outlay, it is said, will secure true Greenwich time to every City establishment.
An account of what has been done at the Greenwich Observatory, as well as of what is in progress,
is given in the annual report of the Astronomer- Royal, and the results are issued from time to time in a more substantial form in the shape of such works as the Astronomer-Royal's |
(). More recently the subjects of solar photography and spectroscopy have been added to the routine investigations of the Observatory. From the annual report published in we learn that the system of time-signals, originating in the Observatory and disseminated by the telegraph through the whole of England, and to Scotland and Ireland, continued to spread, and that it now appeared to be a national institution. The clock has been maintained in all the accuracy that is required for post-office purposes, with scarcely a failure; and the clock has been so efficiently regulated, under the check of automatic report to the Observatory, that on per cent. of the days of the year its error is below . In concluding his report, Sir George Airy remarks that the Observatory was expressly built for the aid of astronomy and navigation, for
|promoting methods of determining longitude at sea, and, as the circumstances that led to its formation show, more especially for determination of the moon's motions. All these imply as their step the formation of accurate catalogues of stars, and the determination of the fundamental elements of the solar system. These objects have been steadily pursued from the foundation of the observatoryin way by Flamsteed, in another way by Halley, and by Bradley in the early part of his career; in a form by Bradley in his later years, by Maskelyne (who contributed most powerfully to lunar and chronometric nautical astronomy), and for a time by Pond; then, with improved instruments, by Pond, and by himself (Sir G. B. Airy) for some years, and subsequently with the instruments now in use. It has been his own intention|
|to maintain the principles of the long-established system in perfect integrity, varying the instruments, the modes of employing them, and the modes of utilising the observations by calculation and publication, as the progress of science might require.|
Viewing the instruments, however, now in use, and the increase of expenses, which were lower than the work done, the Astronomer-Royal expresses a hope that the National Observatory will always remain on the site where it was planted, and which early acquired the name of
The Observatory is annually inspected by a body of scientific persons of high standing, who are commissioned by the Government of the day to see that the institution is maintained in a state of efficiency.
[extra_illustrations.6.207.1] This park
 See ante, p. 165.
[extra_illustrations.6.207.3] George Cruikshank
[extra_illustrations.6.208.1] Greenwich Park, particularly at fair time
 See ante p. 165.
 See ante, p. 196.
[extra_illustrations.6.215.1] Dr. Bradley
[extra_illustrations.6.215.2] Dr. Maskelyne
[extra_illustrations.6.217.1] Admiral Superintendent's Office