ters whilst I was in England; but now you may take the following account from me as an eye-witness, but you must think I could not have time in that short period while I stayed with him, (wich in all was not above an hour and a half,) to look nicely on every part in't, nor could I civilly be so inquisitive, and ask so many questions of one that was a perfect stranger to me, at my first visit, as thoroughly to make me understand the motion and all its parts; so you must be content with what I observed then, and can remember now, which is as follows: - It stands up against the wall like a clockGa naar voetnoot4). The outward dial-plate, where the great circle of the ecliptick is described, containing within it all those of the planets, placed according to the hypothesis of Copernicus, is about two foot square. This shows you at once the minute, hour, day of the month and year, with the exact postures and aspects that all the planets bear to the sun and one another at that very moment, and also the site of the satellites in respect of their middle planets, viz. the three of ♄, and the four of ♃ - these and all the planets absolve their course, just in the same time as they do in the heavens. Here you have all retrogradations, excentricitys, and other irregular motions described. He told me that in 1682, when Saturn and Jupiter were in conjunction several times by their retrograde motionGa naar voetnoot5), that they were so just as often in his
machine as in the heavens. He has not here (for he could [not] with convenience) made the planets, and the diameter of these circles they describe answer according to that proportion they truly bear to one another; but this he has done by a smaller scheme in one corner of his plate, according to the latest observations he and the Parisian astronomers could make. He complained much that the motion of Saturn was not yet certainly regulated by any of the astronomers. I observed its motion was far more excentrick on his plate than any of the rest of the planets. In the inside 't is a very plain piece of work, consisting of not above eight or nine wheels. As I could discern, the chief or principle motion that sets these agoing is not a pendulum, but a balance regulated by springs, as those of pendulum watches are. He can with a key turn the whole engine about, (wich he did,) and set all the wheels agoing, so as to put it to any day that is to come for these three hundred years, and so find out how the posture of the planets will be then. Yet after all this, 'tis nothing more than an ingenious curiosity, and is so far srom being so exact as to supply the place of ephemerides as I imagine 'tis of little or no use at all; for I asked him could he by help of it exactly determine an ecclipse, and I observed he would not give me a positive answer, as being loath to confess the imperfections of his contrivance to me that seemed to admire it so much as I did. You may see such a sort of an engine described in your last volume of the ‘Journal des Scavans’, in the first monthGa naar voetnoot6). After this he carried me into his garden and showed me every particular thing belonging to his
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contrivance which he describes in that little tract I sent you by my lastGa naar voetnoot7). His object-glass, of which he speaks there, he estimates much. 'Tis of both sides convex, and, as he told me, ground by himself. Within these two months he has seen several spots in the sunGa naar voetnoot8), I would have you observe whether you can discern any in your glasses.’ |
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voetnoot1)
- Thomas Molyneux, fils du Captain Samuel Molyneux et de Margaret Dowdal, naquit à Dublin, le 14 avril 1661. A l'âge de 15 ans, il fut inscrit comme étudiant à l'Université de Dublin, où, sept ans plus tard, il prit ses degrés de Master of Arts et de Bachelor of medecine. Après avoir passé quelques mois à Londres, où il rencontra Flamsteed, Hooke, Grew et plusieurs autres membres de la Société Royale, à Cambridge et à Oxford, il se rendit, en automne 1683, en Hollande, où il visita Haarlem, Amsterdam, Utrecht et se fixa à Leiden pour y étudier la médecine. Son frère, William, vint le visiter en juin 1685. En août, Thomas et William se rendirent ensemble à Paris, d'où William retourna à Dublin en octobre. Thomas se proposa de continuer son voyage jusqu'en Italie, mais il fut rappelé par son père, à cause de l'état incertain des affaires publiques après la mort de Charles II. Il séjourna quelque temps à Londres, où il fut élu membre de la Société Royale, le 3 novembre 1686. Thomas retourna en avril 1687 à Dublin et, après y avoir obtenu le doctorat, s'y établit comme médecin. Les troubles anti-protestants qui éclatèrent en Irlande, après l'arrivée de William III en Angleterre, obligèrent les deux frères à émigrer à Chester; ils ne retournèrent à Dublin qu'après la bataille de la Boyne, en juillet 1690. En 1693, Thomas épousa Catharina Howard. Il fut Fellow of the King and Queen's College of Physicians in Ireland, Professor of the Practice of Physic à l'Université de Dublin en 1717, puis State Physician et Physician General de l'armée, et mourut en
1733.
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- William Molyneux, frère aîné du précédent, né à Dublin le 17 avril 1656. De 1684 à 1689, il fut surveyor general of the King's buildings. Comme physicien il est principalement connu par son ouvrage: Dioptrica nova, paru en 1692. Il mourut de la pierre, à Dublin, le 11 octobre 1698. Son fils Samuel, né en juillet 1689, mort le 13 avril 1728, secrétaire du Prince de Galles et plus tard commissaire de l'Amirauté, fut le collaborateur de James Bradley dans la découverte de l'aberration.
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voetnoot3)
- The Dublin University Magazine A Literary and Political Journal, Vol. XVII. July to December 1841. Dublin: William Curry, Jun. and Company. W.S. Orr and Company London. mdcccxli, in-8o., pp. 486 et suiv. D'après Birch, History, IV, p. 341, la lettre fut lue dans la séance du 20 octobre 1684 de la Dublin Society. A notre demande, M.J. de Courcy Mac-Donnell, bibliothécaire de la Public Library à Dublin, a eu l'obligeance de nous faire connaître que la lettre avait été publiée dans le Magazine. Elle fait partie d'une notice étendue sur Sir Thomas Molyneux, tirée principalement de la correspondance des deux frères. M. de Courcy Mac-Donnell a bien voulu nous prêter le volume. Les lettres de Thomas contiennent plusieurs détails sur Chr. Huygens et quelques autres savants de l'époque. Nous en extrayons ce qui suit.
A Thomas, qui avait transmis quelques informations inexactes sur Huygens, William répond: ‘What you tell me of Hugenius does but the more confound, and not at all alter my doubt. You tell me he invented pendulum watches, (you mean watches governed by a regulator, as they call it), but did he apply pendulums or swig-swaggs to clocks? I always took it to be the same man did both, and so you 'l find it; and besides, you seem to contradict yourself in saying he is the author of all those mathematical pieces, and yet say not apply pendulum to clocks; I mean his Horologium, printed at the Hague, 1658, 4to, as also his Horologium Oscillatorium, printed at Paris, 1673, fol. You are much out when you say you believe pendulums were applied to clocks before a man of fifty years of age was born. I assure you pendulums were never so used till anno 1658, upon Hugenius' fore mentioned book; so that if Huygens be now but fifty years he was about twenty-four years old when he invented that, which I can hardly conceive. If you know any thing more to rectify me, pray do. When I say a thing is impracticable (as I said of his astronomia compend.) I do not mean 't is absolutely impossible to effect, for I know many things are to be done that will not be used, because perhaps the inconvenience may be greater than the convenience.
Thomas répond: ‘I can 't but wonder you raise so many scruples about Hugenius; take it then for certain, that there neither is nor even was but one Christianus Hugenius, Constantini Domini de Zulichem Filius, the gentleman I was lately to see, the author of the Systema Saturnium, and therefore, as your self argues, author of the Horologium Oscillatorium. His father, an old man of ninety-four years of age [en réalité 88], still alive, the Herr von Zulichem, no mathematician, but noted for his poetry, both in Dutch and Lattin; he has two sons besides this Christian (both noblemen or lords) who has no title besides that of joncker or jonck-heer - the word the Dutch use for expressing a nobleman's son, and none else. I was directed to inquire for him by the name Joncker Christian; if any of the books gives him the title of Zulichem (tho' I can't think any of them do) it is according to high German's custom, who gives the title of the father to all the children, young and old. I may be mistaken in denying him the invention of applying pendulums to clocks, being misled by the thought of its being so ancient; but this had no reason to make you doubt in the least of that matter, when you know it to be otherwise. You must think I did not ask him his age; he may be more than fifty for aught I know (Huygens avait alors 55 ans), yet by his countenance I should take him to be rather less than more. He has lived many years in France, and for his invention in clock-work I suppose, upon what you say, the adjustment of pendulums to clocks, received a great reward from the French King, and also a yearly pension; whether that is still continued I can 't say; perhaps not. which may be a reason why he is come to Holland, and designs here to stay.’
Au sujet de quelques membres de la Société Royale, Thomas écrivit, le 9 juin 1683, de Londres: ‘Mr. Flamsteed I take a free, affable, and humble man, not at all conceited or dogmatical, as for his knowledge, in that part of learning he professes, I leave you to judge. I was but a short time in Mr. Boyle's company, and therefore am not fit to give you any sort of character of him. He stutters, though not much, speaks very slow, and with many circumlocutions, just as he writes. Though I have seen Mr. Hook, yet I had no conversation with him; but I am told that he is the most ill-natured, self-conceited man in the world, hated and despised by most of the Royal Society, pretending to have had all other inventions when once discovered by their authors to the world.’
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