I explain and assess here Huygens’ concept of relative motion. I show that it allows him to ground most of the Law of Inertia, and also to explain rotation. Thereby his concept obviates the need for Newton’s absolute space. Thus his account is a powerful foundation for mechanics, though not without some tension.
This paper explores the possibility of constructing a Cartesian space-time that can resolve the dilemma posed by a famous argument from Newton's early essay, De gravitatione. In particular, Huygens' concept of a center-of-mass reference frame is utilized in an attempt to reconcile Descartes' relationalist theory of space and motion with both the Cartesian analysis of bodily impact and conservation law for quantity of motion. After presenting a modern formulation of a Cartesian space-time employing Huygens' frames, a series of (...) Newtonian counter-replies are developed in order to estimate the viability of this relationalist project. (shrink)
In 1665, in a response to a question posed by Robert Boyle, Spinoza gave a definition of the coherence between bodies in the universe that seems to be inconsistent both with what he had written in a previous letter to Boyle (1661) and with what he would later write in his main work, the Ethics (1677). Specifically, Spinoza’s 1665 letter to Boyle asserts that bodies can adapt themselves to another body in a non-mechanistic way and absent the agency of an (...) external cause. This letter – Letter 32 – seems, therefore, to be in clear contradiction with the metaphysical determinism that is an important and characteristic element of his philosophy. This article suggests that the viewpoint expressed by Spinoza in Letter 32 may have been inspired by a spectacular discovery made by Christiaan Huygens a few months prior, namely, the self-synchronization of pendulum clocks. As I argue in this article, this new, hypothesized link to Huygens’ pendulum experiments may account for Spinoza’s otherwise paradoxical answer to Boyle in Letter 32. (shrink)
Quels furent les relations de Christiaan Huygens avec les chimistes qu'il eut l'occasion de fréquenter pendant son séjour parisien? A l'examen, elles furent moins distantes que ne le laissent supposer les quelques déclarations fracassantes qui parsèment sa correspondance. Néanmoins, il est difficile d'affirmer qu'il y eut, entre Huygens et la pensée chimique en général, une sympathie qui aurait pu aller au-delà des rencontres individuelles.
I address a question recently raised by Simon Saunders [Phil. Sci. 80: 22-48 ] concerning the relationship between the spacetime structure of Newton-Cartan theory and that of what I will call "Maxwell-Huygens spacetime". This discussion will also clarify a connection between Saunders' work and a recent paper by Eleanor Knox [Brit. J. Phil. Sci. 65: 863-880 ].
Ever since they began to take an interest in lens grinding, the brothers Christiaan and Constantijn Huygens searched for high-quality glass to turn in to lenses. Historical research in combination with optical measurements on preserved lenses has allowed the verificationof the lenses ground by the brothers, and also provided information on who helped them with the necessary knowledge and material.
Summary Until recently it was believed that Christian Huygens? earliest publication of his pendulum invention was Horologium of 1658. He published the more famous general treatise, Horologium Oscillatorium, fifteen years later in 1673. Two years ago, an article1 suggesting an unknown collaboration in developing the clock pendulum between Huygens and the Paris clockmaker Isaac Thuret, presented the evidence of Benjamin Martin, an 18th century educationalist and retailer of scientific material. Martin described a Huygens publication of 1657 and (...) reproduced the illustration it contained. This illustration shows a different clock from the one drawn in Horologium and different also from those previously considered as Huygens? earliest surviving examples. However, the illustration is similar to part of a plate in Horologium Oscillatorium and this similarity caused one historian to cast doubt on the existence of the 1657 publication.2 This article, with information presented for the first time, seeks to prove the existence of that work and thereby establish it in the canon of Huygens? writings while re-examining the invention in the light that it casts. 1Whitestone, Sebastian, ?The Identification and Attribution of Christiaan Huygens? First Pendulum Clock', Antiquarian Horology, December (2008), 201?222. 2Plomp, R., ?Letter', Antiquarian Horology, December (2009), 714?17. See also author's reply, ibid, 717?19. (shrink)
When Christiaan Huygens prepared the 1686/1687 expedition to the Cape of Good Hope on which his pendulum clocks were to be tested for their usefulness in measuring longitude at sea, he also gave instructions to Thomas Helder to perform experiments with the seconds-pendulum. This was prompted by Jean Richer's 1672 finding that a seconds-pendulum is 1 1/4 lines shorter in Cayenne than in Paris. Unfortunately, Helder died on the voy¬age, and no data from the seconds-pendulum ever reached Huygens. (...) He nevertheless did receive data from his clocks on the return-voyage from the Cape of Good Hope to Texel. When he first calculated the ship's course according to these data, it appeared to have gone straight through Ireland. He then tried introducing a correction to the data, based on an idea he had previously entertained as a possible explanation of Richer's finding: he corrected the observed time to com¬pen¬sate for a reduction in the effect of gravity from the Poles to the Equator resulting purely from the Earth's rotation. His newly calculated course convinced him that this rotational effect is the sole source of any variations in gravity with latitude. This paper examines Huygens's correc¬tions to the data and his reasoning from the new course to the conclusion that nothing else causes a variation in gravity. In the process, we show that Huygens had cogent empirical reasons to reject Isaac Newton's theory of universal gravity, which predicted a some¬what larger variation in gravity. (shrink)
In this essay, I will scrutinize the differences between Galileo's and Huygens's demonstrations of free fall, which can be found respectively in the Discorsi and the Horologium, from a mathematical, representational and methodological perspective. I argue that more can be learnt from such an analysis than the thesis that Huygens re-styled Galilean mechanics which is a communis opinio. I shall argue that the differences in their approach on free fall highlight a significantly different mathematical and methodological outlook.
Entre les premiers développements de la mécanique galiléenne et la publication des Principia de Newton, s’est jouée une transformation radicale de la philosophie naturelle des modernes. Mathématiques, sciences de la nature et techniques de précision ont façonné d’une part une nouvelle manière, active et opératoire, d’interroger la nature, et d’autre part une image du monde fondée sur l’idée d’une rationalité intégrale des phénomènes.Interlocuteur infatigable de Mersenne, Galilée, Descartes, Leibniz ou Newton, Christiaan Huygens a assuré un lien nécessaire pour son (...) époque entre l’assimilation critique des Principes de la philosophie de Descartes, dont il retient l’exigence d’intelligibilité dans la conduite de la science, et la réception – critique elle aussi – des Principes mathématiques newtoniens. La méthode de Huygens se structure dans les apports cartésien et galiléen : choc des corps, oscillations du pendule, étude de la force et du mouvement en tant qu’expression de rapports géométriques, caractérisation de la nature de la lumière sont autant de champs dans lesquels il est impossible de ne pas voir l’imprégnation d’un questionnement philosophique permanent. C’est donc en philosophe tout autant qu’en physicien qu’il s’oppose aux définitions newtoniennes de la lumière et de la pesanteur. (shrink)
A letter written by Christiaan Huygens to David Gregory is published here for the first time. After an introduction about the contacts between the two correspondents, an annotated English translation of the letter is given. The letter forms part of the wider correspondence about the ‘new calculus’, in which L'Hospital and Leibniz also participated, and gives some new evidence about Huygens's ambivalent attitude towards the new developments. Therefore, two mathematical passages in the letter are discussed separately. An appendix (...) contains the original Latin text. (shrink)
How should we assess the appeal of multiple scientific theories when they can all explain a particular empirical phenomenon of interest? We contrast Huygens' and Fermat's explanations of the law of refraction of light and find that neither dominates the other when considering multiple criteria for assessing the overall appeal of a scientific theory. The absence of teleology in Huygens' account is a strong plus compared to Fermat's. But Huygens' wave theory scores less well with respect to (...) other desiderata for a scientific theory. In this case, there does not appear to be a clear winner, nor need there be one. (shrink)
A sketch is given of a way of looking at science. Research is viewed as a complex of cognitive processes with theoretical and experimental sides. A distinction is made between context of discovery and context of presentation. In the latter "paragons of science" come into play. From this platform the "theory of research" of Christian Huygens is examined, in its contemporary situation between Baconian empiricism and Cartesian rationalism, and in connection with Galileo's outlook on method. Huygens' attitude on (...) legitimating the results of his research production is also examined. The paper employs a method of case study, which is also discussed. (shrink)
In 1672, inspired by the wave theory of Ignace Gaston Pardies, Christiaan Huygens made his first attempt to explain the sine law of refraction, but in 1673 he abandoned his plans owing to difficulties concerning double refraction. Huygens was able to explain double refraction on 6 August 1677 after his discoveries of the axis of symmetry of the crystal and of ‘Huygens's principle’. On 6 August 1679, he wrote: ‘I have found the confirmation of my theory of (...) light and of refraction’, and then described an ‘experimentum crucis’ to decide between his theory and a rival hypothesis. A study of caustics may have led Huygens to the discovery of ‘Huygens's principle’. (shrink)
La correspondance entre Descartes et Huygens, quoique maintenant absorbée dans le corpus général des lettres de Descartes, garde son intérêt et son importance propre. A part son caractère unique, comme série complète de lettres échangées entre deux hommes d’une distinction si différente, elle nous montre avec quelle précaution il nous faut accepter le texte des lettres de Clerselier et le récit de Baillet sur la vie de Descartes en Hollande. Et comme toutes les vies de Descartes reposent finalement sur (...) Clerselier et Baillet, notre Correspondance nous montre qu’il est nécessaire d’examiner à nouveau tout le problème. (shrink)
Summary A sketch is given of a way of looking at science. Research is viewed as a complex of cognitive processes with a theoretical and experimental sides. A distinction is made between context of discovery and context of presentation. In the latter paragons of science come into play. From this platform the theory of research of Christian Huygens is examined, in its contemporary situation between Baconian empiricism and Cartesian rationalism, and in connection with Galileo's outlook on method. Huygens' (...) attitude on legitimating the results of his research production is also examined. The paper employs a method of case study, which is also discusses. (shrink)
Christiaan Huygens sketched several designs for a simple microscope in his notebooks and in letters to his brother in the course of the year 1678. In this paper the various designs are described. The differences between them mainly concern the improvement of the quality of the image and easy manipulation of the specimens. Huygens' attention to these details is discussed in relation to his own microscopical investigation of micro-organisms. Huygens' designs were widely known in the circles of (...) the learned in Paris, particularly a design characterized by a diaphragm revolver and a specimen revolver. This design was adopted by several instrument makers, who copied the basic construction but changed the appearance. This study substantiates Huygens' influence on the development of contemporary simple microscopes. Moreover, Huygens' approach to the subject of the microscope and microscopy is a good example of the way he usually worked. (shrink)
RésuméLe but de cet article est ?on;étudier quelques aspects des rapports entre Huygens et Spinoza. Après un court examen de ľoptique des deux auteurs, nous montrons que cette science a servi de paradigme à la métaphysique du philosophe. Nous considérons aussi bien la méthode que le contenu . Mais il y a ?on;autres paradigmes: la mécanique pendulaire, par exemple, dont la contradiction avec ľoptique peut être atténuée, grâce à la géométrie de Huygens ; ou encore le début de (...) la théorie des probabilés, au moyen de laquelle nous présentons une nouvelle interpretation des fins de ľElhique.SummaryThe purpose of this article is to study some aspects of the relations between Huygens and Spinoza. After a short examination of the two authors' optics, we show that this science has been used as a “paradigm” for philosopher's metaphysics. We take account of the method as well as the matter . But there are other paradigms: pendulum mechanics, for example, those contradiction with optics may be reduced, thanks to Huygens' geometry ; or probability theory's beginning, with which we present a new explanation of the aims of Ethics.ZusammenfassungIn diesem Artikel werden einige Aspekte des Verhältnisses zwischen Huygens und Spinoza untersucht. Nach einer Untersuchung der Optik der beiden Autoren wird gezeigt, dass diese Wis‐senschaft als Paradigma für die Metaphysik des Philosophen gedient hat. Wir ziehen sowohl die Methode als auch den Inhalt in Betracht. Es gibt aber auch andere Paradigmen: die Mechanik des Pendels, z. B., deren Widerspruch mit der Optik dank der Geometrie Huygens' abgeschwächt werden kann; oder auch der Beginn der Wahrscheinlichkeitstheorie, mit deren Hil‐fe wir eine neue Interpretation der Zwecke in der Ethik vorlegen. (shrink)
ABSTRACTThis paper deals with the book Cosmotheoros, in which Christiaan Huygens presented his concept of a universe made up of many inhabited planets. Recent interpreters of this work have focused especially on cosmological issues presented in the book. Cosmotheoros, however, comprises also various philosophical ideas. In this paper I want to focus on the concept contemplator coeli – stargazer. The stargazer was the embodiment of the philosophical ideal of the contemplative way of life that appeared in classical philosophy and (...) astronomy. I want to argue that Huygens followed on from the idea of the stargazer and used it in his hypothetical construction of extra-terrestrial life. At the same time, however, he altered this idea in such a way that it corresponded better to the ideals of science at the end of the seventeenth century. In Huygens’ concept, the noble contemplator coeli turned into the modern scientist who works with other scientists on the advancement of mankind’s knowledge of nature. Huygens’ stargazers are a good example of how strikingly the basic assumptions of knowledge of nature in the early modern period changed with regard to classical antiquity. (shrink)
In the histories of science, technology and aviation Christiaan Huygens has been unjustly neglected. Documents in the corpus of his works show a life-long interest in the problem of human flight together with some considerable anticipations of, and contributions to, its solution. He was among the first, if not the first, in perceiving the potential of the heavier-than-air approach. He clearly recognized the need for a powerful, mechanical motive source. He stated the first laws of aerodynamics and conceived the (...) modern propeller for propulsion. He was the first to conceive of the aeroplane. His approach to the problem of flying was both global and scientific. (shrink)
In 1662 Christiaan Huygens carried out the famous Torricelli experiment to test the existence of atmospheric pressure by inserting the apparatus in the glass receiver of a vacuum pump, and evacuating the air inside it. He reported that when the air was exhausted, a column of water remained suspended in a 4-foot tube. This unexpected result was in stark contrast with earlier experiments of Boyle and Hooke that apparently had confirmed Torricelli’s explanation that such a water column was supported (...) by outside air pressure, and would fall when the air was removed. Huygen’s “anomalous suspension” led to the continuation of controversies in the seventeenth century about the nature of the vacuum that these experiments were expected to resolve. Surprisingly, the origin of Huygens’ unexpected result has remained a puzzle up to the present time. In this paper, I discuss the dynamics of such a column of water under the experimental conditions reported by Boyle and by Huygens, that turned out to be different, and present the results of a replication of their experiments with a modern vacuum pump. Contrary to the conventional explanations of these experiments, I demonstrate that in the Boyle–Hooke version of this experiment, the water column descends initially because it is forced down by the gas pressure due to air dissolved in the water which is released inside the Torricelli tube after the external pressure is sufficiently decreased. Huygens, however, first removed this trapped air before he carried out his experiment. In the absence of this internal gas pressure, the early rudimentary vacuum pumps were inadequate to decrease the air pressure sufficiently inside the receiver to demonstrate the descent of a Torricelli column of airless water 4-foot in height or less. (shrink)
I will present evidence that nature does not optimize in the sense of Fermat's principle of least time, contrary to what Schoemaker's unintentionally ambiguous exposition might suggest. First, Huygens' principle, an alternative nonteleological account of Snell's law, is outlined. Second, I confront Fermat's principle with a substantive conceptual problem.
The Royal Society possesses three long-focus simple lenses of diameters 195, 210 and 230 mm, all inscribed with the signature ‘C. Huygens’ and various dates in the year 1686. These prove to have been made by Constantine Huygens, the elder brother of the famous Christiaan Huygens. All three lenses have been examined by a variety of physical and chemical methods, both to define their optical characteristics and to establish the composition of dated samples of late-seventeenth-century Continental glass. (...) The focal lengths of 37·9, 50·1 and 65·2 metres found by combination agree with Huygens' own values of 122, 170 and 210 feet respectively, and are so great that practical employment of the lenses in aerial telescopes has rarely been achieved. All are made from the same very poor glass—a heterogeneous and discoloured potash-rich ‘forest glass’—with a refractive index of 1·516, a costringence of 60, and a density of 2·5 g cm−3. The three lenses were ground with just two concave laps, of radii of curvature 27·11 and 71·15 metres, one lens being plano-convex to a high degree of accuracy. A claim by previous investigators that one lens was a ‘light flint’ glass has been disproved. (shrink)
It is well known that Hooke's wave theory of light, set forth in his Micrographia of 1665, is viewed as a step towards Huygens's famous theory of light. This view depends mostly on some short remarks given by Huygens in his Traité de la Lumi`ere and the earlier Projet du Contenu de la Dioptrique . Huygens's personal copy of Micrographia was believed to be lost until found at Braunschweig University Library by the author three years ago. It (...) is annotated at Observ. IX only, where Hooke deals with his wave theory of light and colours. This article provides a short review of Hooke's theory, and an interpretation of Huygens's annotations, which show clearly the first steps towards the opinions he was to express in his Traité de la lumi`ere, particularly methodological ones. Furthermore, a short comparison is here drawn with Huygens's annotations in his copy of Ango's L'optique divisée en trois livres, which show similar patterns of reasoning. (shrink)
Starting with the analysis of the diary kept by Constantijn Huygens Jr in the second half of the 17th century, this book sketches a panoramic view of life among Dutch regents and at the court of William and Mary, including an eyewitness account of the Glorious Revolution, and highlighting themes such as scientific progress, book and art collecting.
: This paper first discusses the current historical and philosophical framework forged during the last century to account for both the history and the epistemic status of Newton's theory of general gravitation. It then examines the conflict surrounding this theory at the close of the seventeenth century and the first steps towards the revolutionary shift in rational mechanics in the eighteenth century. From a historical point of view, it shows the crucial contribution of the Cartesian mechanistic philosophy and Leibnizian analytic (...) methods to the emergence of so-called Newtonian mechanics which can also be fairly characterized as a synthetic theory of attraction. From a philosophical standpoint, the paper suggests that the reworking of Newton's theory in the 18th century is better understood in a theoretical framework that reconciles Kuhn's notion of "invisible revolution" rather than his notion of "normal science" with Whewell's ascription of the completion of dynamical studies to the post Newtonian period. (shrink)