Great Astronomers Part 9

Such was his enthusiasm that his house, we are told, was incessantly littered with the usual indications of the workman's presence, greatly to the distress of his sister, who, at this time, had come to take up her abode with him and look after his housekeeping. Indeed, she complained that in his astronomical ardour he sometimes omitted to take off, before going into his workshop, the beautiful lace ruffles which he wore while conducting a concert, and that consequently they became soiled with the pitch employed in the polis.h.i.+ng of his mirrors.

This sister, who occupies such a distinct place in scientific history is the same little girl to whom we have already referred. From her earliest days she seems to have cherished a pa.s.sionate admiration for her brilliant brother William. It was the proudest delight of her childhood as well as of her mature years to render him whatever service she could; no man of science was ever provided with a more capable or energetic helper than William Herschel found in this remarkable woman. Whatever work had to be done she was willing to bear her share in it, or even to toil at it una.s.sisted if she could be allowed to do so. She not only managed all his domestic affairs, but in the grinding of the lenses and in the polis.h.i.+ng of the mirrors she rendered every a.s.sistance that was possible. At one stage of the very delicate operation of fas.h.i.+oning a reflector, it is necessary for the workman to remain with his hand on the mirror for many hours in succession. When such labours were in progress, Caroline used to sit by her brother, and enliven the time by reading stories aloud, sometimes pausing to feed him with a spoon while his hands were engaged on the task from which he could not desist for a moment.

When mathematical work had to be done Caroline was ready for it; she had taught herself sufficient to enable her to perform the kind of calculations, not, perhaps, very difficult ones, that Herschel's work required; indeed, it is not too much to say that the mighty life-work which this man was enabled to perform could never have been accomplished had it not been for the self-sacrifice of this ever-loving and faithful sister. When Herschel was at the telescope at night, Caroline sat by him at her desk, pen in hand, ready to write down the notes of the observations as they fell from her brother's lips. This was no insignificant toil. The telescope was, of course, in the open air, and as Herschel not unfrequently continued his observations throughout the whole of a long winter's night, there were but few women who could have accomplished the task which Caroline so cheerfully executed.

From dusk till dawn, when the sky was clear, were Herschel's observing hours, and what this sometimes implied we can realise from the fact that Caroline a.s.sures us she had sometimes to desist because the ink had actually frozen in her pen. The night's work over, a brief rest was taken, and while William had his labours for the day to attend to, Caroline carefully transcribed the observations made during the night before, reduced all the figures and prepared everything in readiness for the observations that were to follow on the ensuing evening.

But we have here been antic.i.p.ating a little of the future which lay before the great astronomer; we must now revert to the history of his early work, at Bath, in 1774, when Herschel's scrutiny of the skies first commenced with an instrument of his own manufacture. For some few years he did not attain any result of importance; no doubt he made a few interesting observations, but the value of the work during those years is to be found, not in any actual discoveries which were accomplished, but in the practice which Herschel obtained in the use of his instruments. It was not until 1782 that the great achievement took place by which he at once sprang into fame.

[PLATE: GARDEN VIEW, HERSCHEL HOUSE, SLOUGH.]

It is sometimes said that discoveries are made by accident, and, no doubt, to a certain extent, but only, I fancy to a very small extent, this statement may be true. It is, at all events, certain that such lucky accidents do not often fall to the lot of people unless those people have done much to deserve them. This was certainly the case with Herschel. He appears to have formed a project for making a close examination of all the stars above a certain magnitude. Perhaps he intended to confine this research to a limited region of the sky, but, at all events, he seems to have undertaken the work energetically and systematically. Star after star was brought to the centre of the field of view of his telescope, and after being carefully examined was then displaced, while another star was brought forward to be submitted to the same process. In the great majority of cases such observations yield really nothing of importance; no doubt even the smallest star in the heavens would, if we could find out all about it, reveal far more than all the astronomers that were ever on the earth have even conjectured. What we actually learn about the great majority of stars is only information of the most meagre description. We see that the star is a little point of light, and we see nothing more.

In the great review which Herschel undertook he doubtless examined hundreds, or perhaps thousands of stars, allowing them to pa.s.s away without note or comment. But on an ever-memorable night in March, 1782, it happened that he was pursuing his task among the stars in the Constellation of Gemini. Doubtless, on that night, as on so many other nights, one star after another was looked at only to be dismissed, as not requiring further attention. On the evening in question, however, one star was noticed which, to Herschel's acute vision seemed different from the stars which in so many thousands are strewn over the sky. A star properly so called appears merely as a little point of light, which no increase of magnifying power will ever exhibit with a true disc. But there was something in the star-like object which Herschel saw that immediately arrested his attention and made him apply to it a higher magnifying power. This at once disclosed the fact that the object possessed a disc, that is, a definite, measurable size, and that it was thus totally different from any one of the hundreds and thousands of stars which exist elsewhere in s.p.a.ce. Indeed, we may say at once that this little object was not a star at all; it was a planet. That such was its true nature was confirmed, after a little further observation, by perceiving that the body was s.h.i.+fting its place on the heavens relatively to the stars. The organist at the Octagon Chapel at Bath had, therefore, discovered a new planet with his home-made telescope.

I can imagine some one will say, "Oh, there was nothing so wonderful in that; are not planets always being discovered? Has not M. Palisa, for instance, discovered about eighty of such objects, and are there not hundreds of them known nowadays?" This is, to a certain extent, quite true. I have not the least desire to detract from the credit of those industrious and sharp-sighted astronomers who have in modern days brought so many of these little objects within our cognisance. I think, however, it must be admitted that such discoveries have a totally different importance in the history of science from that which belongs to the peerless achievement of Herschel. In the first place, it must be observed that the minor planets now brought to light are so minute that if a score of them were rolled to together into one lump it would not be one-thousandth part of the size of the grand planet discovered by Herschel. This is, nevertheless, not the most important point. What marks Herschel's achievement as one of the great epochs in the history of astronomy is the fact that the detection of Ura.n.u.s was the very first recorded occasion of the discovery of any planet whatever.

For uncounted ages those who watched the skies had been aware of the existence of the five old planets--Jupiter, Mercury, Saturn, Venus, and Mars. It never seems to have occurred to any of the ancient philosophers that there could be other similar objects as yet undetected over and above the well-known five. Great then was the astonishment of the scientific world when the Bath organist announced his discovery that the five planets which had been known from all antiquity must now admit the company of a sixth. And this sixth planet was, indeed, worthy on every ground to be received into the ranks of the five glorious bodies of antiquity. It was, no doubt, not so large as Saturn, it was certainly very much less than Jupiter; on the other hand, the new body was very much larger than Mercury, than Venus, or than Mars, and the earth itself seemed quite an insignificant object in comparison with this newly added member of the Solar System. In one respect, too, Herschel's new planet was a much more imposing object than any one of the older bodies; it swept around the sun in a majestic orbit, far outside that of Saturn, which had previously been regarded as the boundary of the Solar System, and its stately progress required a period of not less than eighty-one years.

King George the Third, hearing of the achievements of the Hanoverian musician, felt much interest in his discovery, and accordingly Herschel was bidden to come to Windsor, and to bring with him the famous telescope, in order to exhibit the new planet to the King, and to tell his Majesty all about it. The result of the interview was to give Herschel the opportunity for which he had so long wished, of being able to devote himself exclusively to science for the rest of his life.

[PLATE: VIEW OF THE OBSERVATORY, HERSCHEL HOUSE, SLOUGH.]

The King took so great a fancy to the astronomer that he first, as I have already mentioned, duly pardoned his desertion from the army, some twenty-five years previously. As a further mark of his favour the King proposed to confer on Herschel the t.i.tle of his Majesty's own astronomer, to a.s.sign to him a residence near Windsor, to provide him with a salary, and to furnish such funds as might be required for the erection of great telescopes, and for the conduct of that mighty scheme of celestial observation on which Herschel was so eager to enter. Herschel's capacity for work would have been much impaired if he had been deprived of the aid of his admirable sister, and to her, therefore, the King also a.s.signed a salary, and she was installed as Herschel's a.s.sistant in his new post.

With his usually impulsive determination, Herschel immediately cut himself free from all his musical avocations at Bath, and at once entered on the task of making and erecting the great telescopes at Windsor. There, for more than thirty years, he and his faithful sister prosecuted with unremitting ardour their nightly scrutiny of the sky. Paper after paper was sent to the Royal Society, describing the hundreds, indeed the thousands, of objects such as double stars; nebulae and cl.u.s.ters, which were first revealed to human gaze during those midnight vigils. To the end of his life he still continued at every possible opportunity to devote himself to that beloved pursuit in which he had such unparalleled success. No single discovery of Herschel's later years was, however, of the same momentous description as that which first brought him to fame.

[PLATE: THE 40-FOOT TELESCOPE AS IT WAS IN THE YEAR 1863, HERSCHEL HOUSE, SLOUGH.]

Herschel married when considerably advanced in life and he lived to enjoy the indescribable pleasure of finding that his only son, afterwards Sir John Herschel, was treading worthily in his footsteps, and attaining renown as an astronomical observer, second only to that of his father. The elder Herschel died in 1822, and his ill.u.s.trious sister Caroline then returned to Hanover, where she lived for many years to receive the respect and attention which were so justly hers. She died at a very advanced age in 1848.

LAPLACE.

The author of the "Mecanique Celeste" was born at Beaumont-en-Auge, near Honfleur, in 1749, just thirteen years later than his renowned friend Lagrange. His father was a farmer, but appears to have been in a position to provide a good education for a son who seemed promising. Considering the unorthodoxy in religious matters which is generally said to have characterized Laplace in later years, it is interesting to note that when he was a boy the subject which first claimed his attention was theology. He was, however, soon introduced to the study of mathematics, in which he presently became so proficient, that while he was still no more than eighteen years old, he obtained employment as a mathematical teacher in his native town.

Desiring wider opportunities for study and for the acquisition of fame than could be obtained in the narrow a.s.sociations of provincial life, young Laplace started for Paris, being provided with letters of introduction to D'Alembert, who then occupied the most prominent position as a mathematician in France, if not in the whole of Europe. D'Alembert's fame was indeed so brilliant that Catherine the Great wrote to ask him to undertake the education of her Son, and promised the splendid income of a hundred thousand francs. He preferred, however, a quiet life of research in Paris, although there was but a modest salary attached to his office. The philosopher accordingly declined the alluring offer to go to Russia, even though Catherine wrote again to say: "I know that your refusal arises from your desire to cultivate your studies and your friends.h.i.+ps in quiet.

But this is of no consequence: bring all your friends with you, and I promise you that both you and they shall have every accommodation in my power." With equal firmness the ill.u.s.trious mathematician resisted the manifold attractions with which Frederick the Great sought to induce him, to take up his residence at Berlin. In reading of these invitations we cannot but be struck at the extraordinary respect which was then paid to scientific distinction. It must be remembered that the discoveries of such a man as D'Alembert were utterly incapable of being appreciated except by those who possessed a high degree of mathematical culture. We nevertheless find the potentates of Russia and Prussia entreating and, as it happens, vainly entreating, the most distinguished mathematician in France to accept the positions that they were proud to offer him.

It was to D'Alembert, the profound mathematician, that young Laplace, the son of the country farmer, presented his letters of introduction. But those letters seem to have elicited no reply, whereupon Laplace wrote to D'Alembert submitting a discussion on some point in Dynamics. This letter instantly produced the desired effect. D'Alembert thought that such mathematical talent as the young man displayed was in itself the best of introductions to his favour. It could not be overlooked, and accordingly he invited Laplace to come and see him. Laplace, of course, presented himself, and ere long D'Alembert obtained for the rising philosopher a professors.h.i.+p of mathematics in the Military School in Paris. This gave the brilliant young mathematician the opening for which he sought, and he quickly availed himself of it.

Laplace was twenty-three years old when his first memoir on a profound mathematical subject appeared in the Memoirs of the Academy at Turin. From this time onwards we find him publis.h.i.+ng one memoir after another in which he attacks, and in many cases successfully vanquishes, profound difficulties in the application of the Newtonian theory of gravitation to the explanation of the solar system. Like his great contemporary Lagrange, he loftily attempted problems which demanded consummate a.n.a.lytical skill for their solution. The attention of the scientific world thus became riveted on the splendid discoveries which emanated from these two men, each gifted with extraordinary genius.

Laplace's most famous work is, of course, the "Mecanique Celeste," in which he essayed a comprehensive attempt to carry out the principles which Newton had laid down, into much greater detail than Newton had found practicable. The fact was that Newton had not only to construct the theory of gravitation, but he had to invent the mathematical tools, so to speak, by which his theory could be applied to the explanation of the movements of the heavenly bodies. In the course of the century which had elapsed between the time of Newton and the time of Laplace, mathematics had been extensively developed.

In particular, that potent instrument called the infinitesimal calculus, which Newton had invented for the investigation of nature, had become so far perfected that Laplace, when he attempted to unravel the movements of the heavenly bodies, found himself provided with a calculus far more efficient than that which had been available to Newton. The purely geometrical methods which Newton employed, though they are admirably adapted for demonstrating in a general way the tendencies of forces and for explaining the more obvious phenomena by which the movements of the heavenly bodies are disturbed, are yet quite inadequate for dealing with the more subtle effects of the Law of Gravitation. The disturbances which one planet exercises upon the rest can only be fully ascertained by the aid of long calculation, and for these calculations a.n.a.lytical methods are required.

With an armament of mathematical methods which had been perfected since the days of Newton by the labours of two or three generations of consummate mathematical inventors, Laplace essayed in the "Mecanique Celeste" to unravel the mysteries of the heavens. It will hardly be disputed that the book which he has produced is one of the most difficult books to understand that has ever been written. In great part, of course, this difficulty arises from the very nature of the subject, and is so far unavoidable. No one need attempt to read the "Mecanique Celeste" who has not been naturally endowed with considerable mathematical apt.i.tude which he has cultivated by years of a.s.siduous study. The critic will also note that there are grave defects in Laplace's method of treatment. The style is often extremely obscure, and the author frequently leaves great gaps in his argument, to the sad discomfiture of his reader. Nor does it mend matters to say, as Laplace often does say, that it is "easy to see"

how one step follows from another. Such inferences often present great difficulties even to excellent mathematicians. Tradition indeed tells us that when Laplace had occasion to refer to his own book, it sometimes happened that an argument which he had dismissed with his usual formula, "Il est facile a voir," cost the ill.u.s.trious author himself an hour or two of hard thinking before he could recover the train of reasoning which had been omitted. But there are certain parts of this great work which have always received the enthusiastic admiration of mathematicians. Laplace has, in fact, created whole tracts of science, some of which have been subsequently developed with much advantage in the prosecution of the study of Nature.

Judged by a modern code the gravest defect of Laplace's great work is rather of a moral than of a mathematical nature. Lagrange and he advanced together in their study of the mechanics of the heavens, at one time perhaps along parallel lines, while at other times they pursued the same problem by almost identical methods. Sometimes the important result was first reached by Lagrange, sometimes it was Laplace who had the good fortune to make the discovery. It would doubtless be a difficult matter to draw the line which should exactly separate the contributions to astronomy made by one of these ill.u.s.trious mathematicians, and the contributions made by the other.

But in his great work Laplace in the loftiest manner disdained to accord more than the very barest recognition to Lagrange, or to any of the other mathematicians, Newton alone excepted, who had advanced our knowledge of the mechanism of the heavens. It would be quite impossible for a student who confined his reading to the "Mecanique Celeste" to gather from any indications that it contains whether the discoveries about which he was reading had been really made by Laplace himself or whether they had not been made by Lagrange, or by Euler, or by Clairaut. With our present standard of morality in such matters, any scientific man who now brought forth a work in which he presumed to ignore in this wholesale fas.h.i.+on the contributions of others to the subject on which he was writing, would be justly censured and bitter controversies would undoubtedly arise. Perhaps we ought not to judge Laplace by the standard of our own time, and in any case I do not doubt that Laplace might have made a plausible defence. It is well known that when two investigators are working at the same subjects, and constantly publis.h.i.+ng their results, it sometimes becomes difficult for each investigator himself to distinguish exactly between what he has accomplished and that which must be credited to his rival. Laplace may probably have said to himself that he was going to devote his energies to a great work on the interpretation of Nature, that it would take all his time and all his faculties, and all the resources of knowledge that he could command, to deal justly with the mighty problems before him. He would not allow himself to be distracted by any side issue. He could not tolerate that pages should be wasted in merely discussing to whom we owe each formula, and to whom each deduction from such formula is due. He would rather endeavour to produce as complete a picture as he possibly could of the celestial mechanics, and whether it were by means of his mathematics alone, or whether the discoveries of others may have contributed in any degree to the result, is a matter so infinitesimally insignificant in comparison with the grandeur of his subject that he would altogether neglect it. "If Lagrange should think," Laplace might say, "that his discoveries had been unduly appropriated, the proper course would be for him to do exactly what I have done. Let him also write a "Mecanique Celeste," let him employ those consummate talents which he possesses in developing his n.o.ble subject to the utmost. Let him utilise every result that I or any other mathematician have arrived at, but not trouble himself unduly with unimportant historical details as to who discovered this, and who discovered that; let him produce such a work as he could write, and I shall heartily welcome it as a splendid contribution to our science." Certain it is that Laplace and Lagrange continued the best of friends, and on the death of the latter it was Laplace who was summoned to deliver the funeral oration at the grave of his great rival.

The investigations of Laplace are, generally speaking, of too technical a character to make it possible to set forth any account of them in such a work as the present. He did publish, however, one treatise, called the "Systeme du Monde," in which, without introducing mathematical symbols, he was able to give a general account of the theories of the celestial movements, and of the discoveries to which he and others had been led. In this work the great French astronomer sketched for the first time that remarkable doctrine by which his name is probably most generally known to those readers of astronomical books who are not specially mathematicians.

It is in the "Systeme du Monde" that Laplace laid down the principles of the Nebular Theory which, in modern days, has been generally accepted by those philosophers who are competent to judge, as substantially a correct expression of a great historical fact.

[PLATE: LAPLACE.]

The Nebular Theory gives a physical account of the origin of the solar system, consisting of the sun in the centre, with the planets and their attendant satellites. Laplace perceived the significance of the fact that all the planets revolved in the same direction around the sun; he noticed also that the movements of rotation of the planets on their axes were performed in the same direction as that in which a planet revolves around the sun; he saw that the orbits of the satellites, so far at least as he knew them, revolved around their primaries also in the same direction. Nor did it escape his attention that the sun itself rotated on its axis in the same sense.

His philosophical mind was led to reflect that such a remarkable unanimity in the direction of the movements in the solar system demanded some special explanation. It would have been in the highest degree improbable that there should have been this unanimity unless there had been some physical reason to account for it. To appreciate the argument let us first concentrate our attention on three particular bodies, namely the earth, the sun, and the moon. First the earth revolves around the sun in a certain direction, and the earth also rotates on its axis. The direction in which the earth turns in accordance with this latter movement might have been that in which it revolves around the sun, or it might of course have been opposite thereto. As a matter of fact the two agree. The moon in its monthly revolution around the earth follows also the same direction, and our satellite rotates on its axis in the same period as its monthly revolution, but in doing so is again observing this same law. We have therefore in the earth and moon four movements, all taking place in the same direction, and this is also identical with that in which the sun rotates once every twenty-five days. Such a coincidence would be very unlikely unless there were some physical reason for it. Just as unlikely would it be that in tossing a coin five heads or five tails should follow each other consecutively. If we toss a coin five times the chances that it will turn up all heads or all tails is but a small one. The probability of such an event is only one-sixteenth.

There are, however, in the solar system many other bodies besides the three just mentioned which are animated by this common movement.

Among them are, of course, the great planets, Jupiter, Saturn, Mars, Venus, and Mercury, and the satellites which attend on these planets. All these planets rotate on their axes in the same direction as they revolve around the sun, and all their satellites revolve also in the same way. Confining our attention merely to the earth, the sun, and the five great planets with which Laplace was acquainted, we have no fewer than six motions of revolution and seven motions of rotation, for in the latter we include the rotation of the sun. We have also sixteen satellites of the planets mentioned whose revolutions round their primaries are in the same direction. The rotation of the moon on its axis may also be reckoned, but as to the rotations of the satellites of the other planets we cannot speak with any confidence, as they are too far off to be observed with the necessary accuracy. We have thus thirty circular movements in the solar system connected with the sun and moon and those great planets than which no others were known in the days of Laplace. The significant fact is that all these thirty movements take place in the same direction. That this should be the case without some physical reason would be just as unlikely as that in tossing a coin thirty times it should turn up all heads or all tails every time without exception.

We can express the argument numerically. Calculation proves that such an event would not generally happen oftener than once out of five hundred millions of trials. To a philosopher of Laplace's penetration, who had made a special study of the theory of probabilities, it seemed well-nigh inconceivable that there should have been such unanimity in the celestial movements, unless there had been some adequate reason to account for it. We might, indeed, add that if we were to include all the objects which are now known to belong to the solar system, the argument from probability might be enormously increased in strength. To Laplace the argument appeared so conclusive that he sought for some physical cause of the remarkable phenomenon which the solar system presented. Thus it was that the famous Nebular Hypothesis took its rise. Laplace devised a scheme for the origin of the sun and the planetary system, in which it would be a necessary consequence that all the movements should take place in the same direction as they are actually observed to do.

Let us suppose that in the beginning there was a gigantic ma.s.s of nebulous material, so highly heated that the iron and other substances which now enter into the composition of the earth and planets were then suspended in a state of vapour. There is nothing unreasonable in such a supposition indeed, we know as a matter of fact that there are thousands of such nebulae to be discerned at present through our telescopes. It would be extremely unlikely that any object could exist without possessing some motion of rotation; we may in fact a.s.sert that for rotation to be entirety absent from the great primeval nebula would be almost infinitely improbable. As ages rolled on, the nebula gradually dispersed away by radiation its original stores of heat, and, in accordance with well-known physical principles, the materials of which it was formed would tend to coalesce. The greater part of those materials would become concentrated in a mighty ma.s.s surrounded by outlying uncondensed vapours. There would, however, also be regions throughout the extent of the nebula, in which subsidiary centres of condensation would be found. In its long course of cooling, the nebula would, therefore, tend ultimately to form a mighty central body with a number of smaller bodies disposed around it. As the nebula was initially endowed with a movement of rotation, the central ma.s.s into which it had chiefly condensed would also revolve, and the subsidiary bodies would be animated by movements of revolution around the central body. These movements would be all pursued in one common direction, and it follows, from well-known mechanical principles, that each of the subsidiary ma.s.ses, besides partic.i.p.ating in the general revolution around the central body, would also possess a rotation around its axis, which must likewise be performed in the same direction. Around the subsidiary bodies other objects still smaller would be formed, just as they themselves were formed relatively to the great central ma.s.s.

As the ages sped by, and the heat of these bodies became gradually dissipated, the various objects would coalesce, first into molten liquid ma.s.ses, and thence, at a further stage of cooling, they would a.s.sume the appearance of solid ma.s.ses, thus producing the planetary bodies such as we now know them. The great central ma.s.s, on account of its preponderating dimensions, would still retain, for further uncounted ages, a large quant.i.ty of its primeval heat, and would thus display the splendours of a glowing sun. In this way Laplace was able to account for the remarkable phenomena presented in the movements of the bodies of the solar system. There are many other points also in which the nebular theory is known to tally with the facts of observation. In fact, each advance in science only seems to make it more certain that the Nebular Hypothesis substantially represents the way in which our solar system has grown to its present form.

Not satisfied with a career which should be merely scientific, Laplace sought to connect himself with public affairs. Napoleon appreciated his genius, and desired to enlist him in the service of the State. Accordingly he appointed Laplace to be Minister of the Interior. The experiment was not successful, for he was not by nature a statesman. Napoleon was much disappointed at the inept.i.tude which the great mathematician showed for official life, and, in despair of Laplace's capacity as an administrator, declared that he carried the spirit of his infinitesimal calculus into the management of business. Indeed, Laplace's political conduct hardly admits of much defence. While he accepted the honours which Napoleon showered on him in the time of his prosperity, he seems to have forgotten all this when Napoleon could no longer render him service. Laplace was made a Marquis by Louis XVIII., a rank which he transmitted to his son, who was born in 1789. During the latter part of his life the philosopher lived in a retired country place at Arcueile. Here he pursued his studies, and by strict abstemiousness, preserved himself from many of the infirmities of old age. He died on March the 5th, 1827, in his seventy-eighth year, his last words being, "What we know is but little, what we do not know is immense."

BRINKLEY.

Provost Baldwin held absolute sway in the University of Dublin for forty-one years. His memory is well preserved there. The Bursar still dispenses the satisfactory revenues which Baldwin left to the College. None of us ever can forget the marble angels round the figure of the dying Provost on which we used to gaze during the pangs of the Examination Hall.

Baldwin died in 1785, and was succeeded by Francis Andrews, a Fellow of seventeen years' standing. As to the scholastic acquirements of Andrews, all I can find is a statement that he was complimented by the polite Professors of Padua on the elegance and purity with which he discoursed to them in Latin. Andrews was also reputed to be a skilful lawyer. He was certainly a Privy Councillor and a prominent member of the Irish House of Commons, and his social qualities were excellent. Perhaps it was Baldwin's example that stimulated a desire in Andrews to become a benefactor to his college. He accordingly bequeathed a sum of 3,000 pounds and an annual income of 250 pounds wherewith to build and endow an astronomical Observatory in the University. The figures just stated ought to be qualified by the words of cautious Ussher (afterwards the first Professor of Astronomy), that "this money was to arise from an acc.u.mulation of a part of his property, to commence upon a particular contingency happening to his family." The astronomical endowment was soon in jeopardy by litigation. Andrews thought he had provided for his relations by leaving to them certain leasehold interests connected with the Provost's estate. The law courts, however, held that these interests were not at the disposal of the testator, and handed them over to Hely Hutchinson, the next Provost. The disappointed relations then pet.i.tioned the Irish Parliament to redress this grievance by transferring to them the moneys designed by Andrews for the Observatory. It would not be right, they contended, that the kindly intentions of the late Provost towards his kindred should be frustrated for the sake of maintaining what they described as "a purely ornamental inst.i.tution." The authorities of the College protested against this claim. Counsel were heard, and a Committee of the House made a report declaring the situation of the relations to be a hard one. Accordingly, a compromise was made, and the dispute terminated.

The selection of a site for the new astronomical Observatory was made by the Board of Trinity College. The beautiful neighbourhood of Dublin offered a choice of excellent localities. On the north side of the Liffey an Observatory could have been admirably placed, either on the remarkable promontory of Howth or on the elevation of which Dunsink is the summit. On the south side of Dublin there are several eminences that would have been suitable: the breezy heaths at Foxrock combine all necessary conditions; the obelisk hill at Killiney would have given one of the most picturesque sites for an Observatory in the world; while near Delgany two or three other good situations could be mentioned. But the Board of those pre-railway days was naturally guided by the question of proximity. Dunsink was accordingly chosen as the most suitable site within the distance of a reasonable walk from Trinity College.

The northern boundary of the Phoenix Park approaches the little river Tolka, which winds through a succession of delightful bits of sylvan scenery, such as may be found in the wide demesne of Abbotstown and the cla.s.sic shades of Glasnevin. From the banks of the Tolka, on the opposite side of the park, the pastures ascend in a gentle slope to culminate at Dunsink, where at a distance of half a mile from the stream, of four miles from Dublin, and at a height of 300 feet above the sea, now stands the Observatory. From the commanding position of Dunsink a magnificent view is obtained. To the east the sea is visible, while the southern prospect over the valley of the Liffey is bounded by a range of hills and mountains extending from Killiney to Bray Head, thence to the little Sugar Loaf, the Two Rock and the Three Rock Mountains, over the flank of which the summit of the Great Sugar Loaf is just perceptible. Directly in front opens the fine valley of Glenasmole, with Kippure Mountain, while the range can be followed to its western extremity at Lyons. The climate of Dunsink is well suited for astronomical observation. No doubt here, as elsewhere in Ireland, clouds are abundant, but mists or haze are comparatively unusual, and fogs are almost unknown.

The legal formalities to be observed in a.s.suming occupation exacted a delay of many months; accordingly, it was not until the 10th December, 1782, that a contract could be made with Mr. Graham Moyers for the erection of a meridian-room and a dome for an equatorial, in conjunction with a becoming residence for the astronomer. Before the work was commenced at Dunsink, the Board thought it expedient to appoint the first Professor of Astronomy. They met for this purpose on the 22nd January, 1783, and chose the Rev. Henry Ussher, a Senior Fellow of Trinity College, Dublin. The wisdom of the appointment was immediately shown by the a.s.siduity with which Ussher engaged in founding the observatory. In three years he had erected the buildings and equipped them with instruments, several of which were of his own invention. On the 19th of February, 1785, a special grant of 200 pounds was made by the Board to Dr. Ussher as some recompense for his labours. It happened that the observatory was not the only scientific inst.i.tution which came into being in Ireland at this period; the newly-kindled ardour for the pursuit of knowledge led, at the same time, to the foundation of the Royal Irish Academy. By a fitting coincidence, the first memoir published in the "Transactions Of The Royal Irish Academy," was by the first Andrews, Professor of Astronomy. It was read on the 13th of June, 1785, and bore the t.i.tle, "Account of the Observatory belonging to Trinity College," by the Rev. H. Ussher, D.D., M.R.I.A., F.R.S. This communication shows the extensive design that had been originally intended for Dunsink, only a part of which was, however, carried out. For instance, two long corridors, running north and south from the central edifice, which are figured in the paper, never developed into bricks and mortar. We are not told why the original scheme had to be contracted; but perhaps the reason may be not unconnected with a remark of Ussher's, that the College had already advanced from its own funds a sum considerably exceeding the original bequest. The picture of the building shows also the dome for the South equatorial, which was erected many years later.

Ussher died in 1790. During his brief career at the observatory, he observed eclipses, and is stated to have done other scientific work.

The minutes of the Board declare that the infant inst.i.tution had already obtained celebrity by his labours, and they urge the claims of his widow to a pension, on the ground that the disease from which he died had been contracted by his nightly vigils. The Board also promised a grant of fifty guineas as a help to bring out Dr. Ussher's sermons. They advanced twenty guineas to his widow towards the publication of his astronomical papers. They ordered his bust to be executed for the observatory, and offered "The Death of Ussher" as the subject of a prize essay; but, so far as I can find, neither the sermons nor the papers, neither the bust nor the prize essay, ever came into being.

There was keen compet.i.tion for the chair of Astronomy which the death of Ussher vacated. The two candidates were Rev. John Brinkley, of Caius College, Cambridge, a Senior Wrangler (born at Woodbridge, Suffolk, in 1763), and Mr. Stack, Fellow of Trinity College, Dublin, and author of a book on Optics. A majority of the Board at first supported Stack, while Provost Hely Hutchinson and one or two others supported Brinkley. In those days the Provost had a veto at elections, so that ultimately Stack was withdrawn and Brinkley was elected. This took place on the 11th December, 1790. The national press of the day commented on the preference shown to the young Englishman, Brinkley, over his Irish rival. An animated controversy ensued. The Provost himself condescended to enter the lists and to vindicate his policy by a long letter in the "Public Register" or "Freeman's Journal," of 21st December, 1790. This letter was anonymous, but its authors.h.i.+p is obvious. It gives the correspondence with Maskelyne and other eminent astronomers, whose advice and guidance had been sought by the Provost. It also contends that "the transactions of the Board ought not to be canva.s.sed in the newspapers." For this reference, as well as for much other information, I am indebted to my friend, the Rev. John Stubbs, D.D.

[PLATE: THE OBSERVATORY, DUNSINK. From a Photograph by W. Lawrence, Upper Sackville Street, Dublin.]

The next event in the history of the Observatory was the issue of Letters Patent (32 Geo. III., A.D. 1792), in which it is recited that "We grant and ordain that there shall be forever hereafter a Professor of Astronomy, on the foundation of Dr. Andrews, to be called and known by the name of the Royal Astronomer of Ireland." The letters prescribe the various duties of the astronomer and the mode of his election. They lay down regulations as to the conduct of the astronomical work, and as to the choice of an a.s.sistant. They direct that the Provost and the Senior Fellows shall make a thorough inspection of the observatory once every year in June or July; and this duty was first undertaken on the 5th of July, 1792. It may be noted that the date on which the celebration of the tercentenary of the University was held happens to coincide with the centenary of the first visitation of the observatory. The visitors on the first occasion were A. Murray, Matthew Young, George Hall, and John Barrett. They record that they find the buildings, books and instruments in good condition; but the chief feature in this report, as well as in many which followed it, related to a circ.u.mstance to which we have not yet referred.

In the original equipment of the observatory, Ussher, with the natural ambition of a founder, desired to place in it a telescope of more magnificent proportions than could be found anywhere else. The Board gave a spirited support to this enterprise, and negotiations were entered into with the most eminent instrument-maker of those days. This was Jesse Ramsden (1735-1800), famous as the improver of the s.e.xtant, as the constructor of the great theodolite used by General Roy in the English Survey, and as the inventor of the dividing engine for graduating astronomical instruments. Ramsden had built for Sir George Schuckburgh the largest and most perfect equatorial ever attempted. He had constructed mural quadrants for Padua and Verona, which elicited the wonder of astronomers when Dr.