DOCSLIB.ORG

Poleni's Instruments to Trace Transcendental Curves "By an Astonishingly Pure and Simple Method" Pietro Milici, [email protected]

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Poleni's Instruments to Trace Transcendental Curves Poleni's instruments to trace transcendental curves "by an astonishingly pure and simple method" Pietro Milici, [email protected] 1. Introduction During the 17th century, mathematicians radically modified their idea of a curve, transitioning from the trace of a machine to the solution of an equation. With that in mind, Descartes and Leibniz introduced theoretical machines (i.e. sketches to be considered mentally but not practically realized) to legitimate the geometrical status of algebraic and transcendental curves obtained as solutions of analytical equations. The general method to construct transcendental curves, in particular, was the solution of the inverse tangent problem by the so-called "tractional motion." At the end of the 19th century, integraphs practically implemented such ideas to mechanically plot the integral of a graphically defined function. A theoretical machine (left, Descartes' 17th c. mesolabe - cf. https://www.youtube.com/watch?v=jhwRBoOK40E) and a geometric-mechanical instrument (right, a 19th c. integraph designed by Abdank-Abakanowicz and produced by the Coradi firm - cf. https://www.historyofinformation.com/detail.php?id=1267). We are interested in the intermediate 18th-century perspective. In particular, we analyse the geometric instruments designed by Giovanni Poleni (1683-1761), polymath and Professor at the University of Padua in Italy. These instruments, which were technically similar to posterior integraphs1, had been described with an engineer's precision in a letter to Jacob Hermann who was Poleni's predecessor in the chair of Mathematics. The letter was included in the Epistolarum Mathematicarum Fasciculus [Poleni (1729)]. 2. The exactness of transcendental curves At the beginning of the 17th century, the development of algebra deeply shocked the mainstream geometrical setting. From this perspective, the groundbreaking Descartes' Géométrie (1637) proposed some criteria to define ideal machines to trace curves (synthetic part, construction by continuous motion) and from the other, it proposed polynomial equations as a suitable language to study such curves (analytic part, algebraic formulas).2 The description of curves by equations introduced the possibility of considering 1 The theoretical components of both instruments are linkages and wheels. While a general theory for linkages has been developed by Kempe with the Universality Theorem (every finite branch of a planar algebraic curve can be traced by an ideal linkage, cf. [Kempe (1876)]), limits of constructions by linkages and wheels have only recently been given by a Differential Universality Theorem (in this case the constructible functions are Differentially Algebraic ones, cf. [Milici (2020)]). 2 Cf. [Bos (2001)]. 1 curves thanks to their symbolic definitions, without an explicit mechanical procedure. That opened the road to an infinity of new curves that, with the mediation of algebra, can be studied with standardized methods. Adopting today's nomenclature, Descartes considered as acceptable curves the algebraic ones (i.e. zeros of a polynomial in two variables), marginalizing the non-algebraic ones, called transcendental. The Cartesian method was not able to solve two geometrical problems, a classical and a new one: to find the area of a curve and to solve the inverse tangent problem. Differently from the direct tangent problem (i.e. to find the tangent to a given curve), such an inverse problem consists in finding the curve whose tangent has to satisfy certain given conditions. The first example of an inverse tangent problem was posed by Florimond de Beaune to Descartes and consisted in finding the curve with constant subtangent (such a solution is an exponential curve). However, while this problem and Descartes' solution were purely theoretical geometrical exercises, the first concrete continuous construction of a curve by inverse tangent conditions was the tractrix, traced by Claude Perrault in Paris (in the 1670s) by dragging an extremity of the chain of a pocket watch: that marked the beginning of a new method for geometrical constructions, the "tractional motion." The cause of such a motion is that, for the friction of the clock on the base plane, the chain becomes in traction and always remains tangent to the curve defined by the watch. Beyond Huygens' preliminary studies, it was Leibniz who used this kind of constructions to justify the geometrical constructability of transcendental curves overcoming Cartesian canon. While for the analytical part he developed the infinitesimal calculus beyond finite algebraic equations, for the synthetic part he used the 3 tractional motion. Perrault's construction of a tractrix by dragging a pocket watch. The image on the left comes from Poleni's Letter to Hermann; on the right, there is a representation of the behaviour when the chain extremity A is pushed to the left starting from the position A0. If up to the end of the 17th century the attention to tractional construction was mainly focused on foundational facets, it was at the beginning of the 18th century that some tractional machines overcame the realm of theoretical ideas and became working instruments, mainly thanks to the introduction of a wheel instead of the dragged heavy load (the watch in Perrault's construction). 4 Such a technical improvement allowed the construction of quite precise machines tracing curves by solving inverse tangent problems, as Perks' and Poleni's machines for the tractrix and the quadrature of hyperbolas (i.e. the 3 Cf. [Bos (1988)], [Tournès (2009)] and [Blasjo (2017)]. 4 While the passage from dragged load to wheel is usually considered as a purely technological modification, it also implies different mathematical principles: while the direction of the wheel directly imposes the direction of the tangent, the geometrical condition posed when dragging a point is a bit more complicated, as visible in the preprint [Milici and Plantevin (2020)]. 2 exponential or related curves). We have to note that today it is believed that these machines were developed independently (differently from the machines of Suardi, a pupil of Poleni).5 3. The "Letter to Hermann" Mathematician, physician, astronomer and also interested in engineering studies, Poleni inaugurated in 1739 a unanimously praised laboratory of experimental physics at the University of Padua ("Teatro di Filosofia Sperimentale"6). However, even before the creation of the laboratory, he was always interested in machines: here we deal with a very particular kind of machines, the mathematical ones, specifically with the ones designed by himself. In his earliest paper [Poleni (1709)], Poleni proposed an operative arithmetic machine based on the ideas of Pascal and Leibniz, that he constructed and that was widely considered simple, easy to use and reliable. But when in 1727, by Marinoni's correspondence, Poleni knew of an improved version of the arithmetic machine by the Viennese Portrait of Giovanni Poleni mechanician Brauer, he destroyed his own and never rebuilt it.7 It is quite interesting that his only other work on mathematical machines followed quite shortly the destruction of the arithmetical one (we propose below an interpretation for this behaviour). In any case, the new machines introduced in the Letter to Hermann belong to a different field of mathematics, moving from arithmetics to geometry. As already introduced, these machines are the ones to trace the tractrix and the logarithmic curve (or exponential, as curves they coincide). They have been realized with particular attention on the precision of the traces and the easiness of the usability: this is well underlined by three recognized mathematicians close to Poleni (the comments of Antonio Conti, Gabriello Manfredi and Jacopo Riccati have been published with the Letter). Specifically, the title of this presentation comes from a comment of Riccati, that was amazed at how Poleni's machines permit to trace transcendental curves "by an astonishingly pure and simple method." From Poleni's foundational perspective, these machines had to prove the geometricity of the tractrix and logarithmic curves. While these curves were well known and generally accepted, for him a curve could only be considered geometrical if constructible by the continuous trace of a simple instrument, guaranteeing adequate usability and accuracy. Anyway, despite initial enthusiastic feedback from contemporaries such as Leonard Euler, such machines were soon forgotten, probably because geometric constructions fell out of favour in mainstream mathematics. While Poleni listed these machines among the artefacts in his cabinet of Experimental Philosophy, the model present today in the Paduan University collection doesn't fit with the description, as we show below. 5 To deepen these machines and also for the sketch of a new machine unifying them, cf. [Crippa and Milici (2019)]. 6 Cf. [Talas (2013)]. 7 Cf. [Hénin (2012)] or https://mathshistory.st-andrews.ac.uk/DSB/Poleni.pdf 3 Poleni's machines for the tractrix (left) and the logarithmic curve (right) in the Letter to Hermann. The machine previously classified as the one for the tractrix and the logarithmic curve (by courtesy of Sofia Talas, curator of the Physics Cabinet of the University of Padua). 4 Indeed, differences between the artefact in the collection and the designs of the Letter are visible since the first glance (e.g. the curved component in the right part). Furthermore, reading the description in Poleni's index,8 the machine differs in materials (wood pieces in the
Load more

Recommended publications
  • Plotting Graphs of Parametric Equations
    Parametric Curve Plotter This Java Applet plots the graph of various primary curves described by parametric equations, and the graphs of some of the auxiliary curves associ- ated with the primary curves, such as the evolute, involute, parallel, pedal, and reciprocal curves. It has been tested on Netscape 3.0, 4.04, and 4.05, Internet Explorer 4.04, and on the Hot Java browser. It has not yet been run through the official Java compilers from Sun, but this is imminent. It seems to work best on Netscape 4.04. There are problems with Netscape 4.05 and it should be avoided until fixed. The applet was developed on a 200 MHz Pentium MMX system at 1024×768 resolution. (Cost: $4000 in March, 1997. Replacement cost: $695 in June, 1998, if you can find one this slow on sale!) For various reasons, it runs extremely slowly on Macintoshes, and slowly on Sun Sparc stations. The curves should move as quickly as Roadrunner cartoons: for a benchmark, check out the circular trigonometric diagrams on my Java page. This applet was mainly done as an exercise in Java programming leading up to more serious interactive animations in three-dimensional graphics, so no attempt was made to be comprehensive. Those who wish to see much more comprehensive sets of curves should look at: http : ==www − groups:dcs:st − and:ac:uk= ∼ history=Java= http : ==www:best:com= ∼ xah=SpecialP laneCurve dir=specialP laneCurves:html http : ==www:astro:virginia:edu= ∼ eww6n=math=math0:html Disclaimer: Like all computer graphics systems used to illustrate mathematical con- cepts, it cannot be error-free.
    [Show full text]
  • MATH 4030 Problem Set 11 Due Date: Sep 19, 2019 Reading
    MATH 4030 Problem Set 11 Due date: Sep 19, 2019 Reading assignment: Preliminary materials, and do Carmo's Section 1.2, 1.3, 1.5 Problems: (Those marked with y are optional.) 1. Compute the Frenet frame fT; N; Bg, curvature κ, and torsion τ of the space curves below (Note that some of the curves may not be parametrized by arc length!): (a) α(s) = 1 (1 + s)3=2; 1 (1 − s)3=2; p1 s , s 2 (−1; 1) 3 3 2 p p (b) α(t) = 1 + t2; t; log(t + 1 + t2) , t 2 R 2. Let α(t) = (t; f(t)), t 2 [a; b], be a parametrization of the graph of a smooth function f :[a; b] ! R. (a) Prove that α is a regular plane curve. R b p 0 2 (b) Show that the arc length of α from t = a to t = b is given by a 1 + (f (x)) dx. (c) Prove that the signed curvature k of the plane curve α is given by f 00(t) k(t) = : [1 + (f 0(t))2]3=2 3. Consider the catenary parametrized by α(t) = (t; cosh t), t 2 [0; b] for some b > 0, (a) Show that the arc length of α(t), t 2 [0; b], is given by sinh b. (b) Reparametrize α(t) by arc length β(s), where s 2 [0; s0]. Find s0. (c) Find the signed curvature kβ of the catenary using the arc length parametrization β(s). 4. Consider the tractrix parametrized by α(t) = (cos t + log tan(t=2); sin t), t 2 [π=2; π], (a) Write down the expression of the arc length of α(t), t 2 [π=2; π=2 + s] for any given s 2 (0; π=2).
    [Show full text]
  • Tractor Trailer Cornering
    TRACTOR TRAILER CORNERING by RAMGOPAL BATTU B. S. , Osmania University, 1963 A MASTER'S REPORT submitted in partial fulfillment of the requirements for the degree MASTER OF SCIENCE Department of Mechanical Engineering KANSAS STATE UNIVERSITY Manhattan, Kansas 1965 Approved by: Major Professor %6 ii TABLE OF CONTENTS NOMENCLATURE lii INTRODUCTION 1 DESCRIPTION OF CORNERING PROBLEM 2 DERIVATION OF EQUATIONS FOR FIRST PORTION OF TRACTRIX ... 4 EQUATIONS FOR SECOND PORTION OF TRACTRIX 11 PRESENTATION OF RESULTS 15 NUMERICAL RESULTS l8 DISCUSSION OF RESULTS 30 CONCLUSIONS 31 ACKNOWLEDGMENT 32 REFERENCES & APPENDIX 34 A. Listing of Fortran Program to solve for the distance between the tractrix curve and the leading curve. Ill NOMENCLATURE R Radius Of path of fifth wheel Ft a x-Co-ordinate of center of curvature Ft in x-y plane b y-Co-ordinate of center of curvature Ft in x-y plane x x-Co-ordinate of path of Trailer in Ft x-y plane Ft y y-Co-ordinate of path of Trailer in x-y plane K x-Co-ordinate of path of Fifth wheel Ft in x-y plane Ft f) y-Co-ordinate of path of Fifth wheel in x-y plane Y Angle indicated in Figure 2 Degrees 9 Angle indicated in Figure 2 Degrees L Length of Trailer Ft V Distance between "the tractrix and the leading curve Ft iv LIST OF FIGURES PAGE FIGURE 2 1 SCHEMATIC OF GENERAL TRACT RIX 2 SCHEMATIC OF A 90° CIRCULAR TURN 2 11 3 TRACTRIX OF A STRAIGHT LINE . 4 TOTAL TRACTRIX INCLUDING THE STRAIGHT LINE MOTION OF THE HITCH POINT 12 5 DIAGRAM SHOWING PARAMETERS USED IN PRESENTING RESULTS 14 6 DISTANCE BETWEEN THE TRACTRIX AND THE LEADING CURVE 16 7 MAXIMUM DIMENSIONLESS DISTANCE V/L VERSUS R/L .
    [Show full text]
  • Raphael, the Catenary-Tractrix Principle of the Transfiguration
    1 of 13 From the desk of Pierre Beaudry RAPHAEL SANZIO: THE CATENARY/TRACTRIX PRINCIPLE OF THE TRANSFIGURATION by Pierre Beaudry 7/21/2009 Raphael’s Transfiguration contains a very disturbing discontinuity representing two different and opposite processes that have baffled critics and admirers alike for centuries. The perplexity of the spectator before this painting lies in the fact that the moment depicted in the upper part of the painting, the actual transfiguration of Christ, does not occur at the same time as the tragic event of the curing of the epileptic boy, in the lower part of the fresco, so that the two scenes appear to be completely foreign, separate, and even opposite subjects. This first impression is neurotic, incomplete, and misleading merely because a true cognitive connection of unity has not been discovered between the two events. On the other hand, if one looks at the whole scene as a metaphor of the creative process, the perplexity is dissipated, and the unity of effect is reestablished. In other words, if the Transfiguration is considered as the reflection of a catenary/tractrix envelopment by inversion of two different times, mortality and immortality, and two opposite movements, local and infinite, woven into an extraordinary singular unity of effect, the enigma of Raphael is resolved. Here, Leonardo da Vinci’s conception of the catenary/tractrix function shows how the human mind works at the same time that one discovers the process of its discovery in a Cusa contracted infinite. That is the central irony of Raphael’s Transfiguration, and the object of this report: to show how Raphael treated the external appearance of the subject in such a manner that it corresponded to the internal nature of the event.
    [Show full text]
  • Recognition and Wonder – Huygens, Tractional Motion and Some
    RECOGNITION AND WONDER Huygens, Tractional Motion and Some Thoughts on the History of Mathematics H.J.M. Bos Note: This is the translation of my inaugural lecture, held .March 20, 1987, as exlraordinar)' professor in the history' of mathematics at the University of Utrecht. The present version differs from the original Dutch text in that the salutation at the beginning and the personal words at the end have been left out and that some errors have been corrected. The original version was separately published (II.J.M. Bos, Vamtit Hcrkt'nning en Verbazing (Utrecht: OMI Grafisch Bcdrijf, 1987); the main text has also been published in Euclides 63, 1987. pp. 65-76. Recognition and wonder. - These two experiences are essential motives behind interest in the past. For that reason I have chosen them as guidelines in presenting my specialty, the history of mathematics, today, upon my accession to office as extraordinary professor. Recognition makes it possible to distinguish historical events and thus initiates the link of past to present. If recognition or affinity is absent, earlier events can hardly, if at all, be historically described. Wonder, on the other hand, is indispensable too. The unexpected, the essentially different nature of occurrences in the past excites the interest and raises the expectation that something can be discovered and learned. History studied without wonder reduces to a mere listing of recognizable past events, which differ from what is familiar only by having another date. Let me illustrate this by two examples which for me strongly evoke the two experien­ ces. In the first example recognition is foremost.
    [Show full text]
  • Arxiv:1707.09532V1 [Math.DG] 29 Jul 2017
    TRACTORS AND TRACTRICES IN RIEMANNIAN MANIFOLDS JESPER J. MADSEN AND STEEN MARKVORSEN Abstract. We generalize the notion of planar bicycle tracks { a.k.a. one-trailer systems { to so-called tractor/tractrix systems in general Riemannian manifolds and prove explicit expressions for the length of the ensuing tractrices and for the area of the do- mains that are swept out by any given tractor/tractrix system. These expressions are sensitive to the curvatures of the ambient Riemannian manifold, and we prove explicit estimates for them based on Rauch's and Toponogov's comparison theorems. More- over, the general length shortening property of tractor/tractrix sys- tems is used to generate geodesics in homotopy classes of curves in the ambient manifold. 1. Introduction The classical tractrix curve appears in virtually every textbook on differential geometry of curves and surfaces { see e.g. [6], [16], [31, p. 239], [21, p. 67], and figure 9 below. The tractrix has a long and fasci- nating history beginning with works of Huygens, Leibniz, Newton, and Euler, see [3]. Not to mention the celebrated watch track experiment by Claude Perrault, long before the invention of the bicycle { see [12], [7], [11]. We quote from [3, p. 1065]:\At a meeting in Paris in 1693 Claude Perrault laid his watch on the table, with the long chain drawn out in a straight line ([4, vol. 3]). He showed that when he moved the end of the chain along a straight line, keeping the chain taut, the watch was dragged along a certain curve. This was one of the early demonstra- tions of the tractrix." arXiv:1707.09532v1 [math.DG] 29 Jul 2017 Moreover, this classical tractrix gives rise to interesting classical sur- faces as well: When rotated around the axis along which the tractrix is pulled, any regular segment of the tractrix curve generates a pseudo- sphere of constant negative Gauss curvature, and the involute of the full classical tractrix curve, including its cusp singularity, is a catenary, which itself, when rotated around the axis, generates a catenoid, i.e.
    [Show full text]
  • The Leibniz Catenary Construction: Geometry Vs Analysis in the 17Th Century
    TITLE&INTRO CONSTRUCTION ANALYSIS FINALE The Leibniz Catenary Construction: Geometry vs Analysis in the 17th Century Mike Raugh www.mikeraugh.org JMM: Joint Mathematics Meetings, Atlanta January 4, 2017 Copyright ©2017 Mike Raugh TITLE&INTRO CONSTRUCTION ANALYSIS FINALE Catenary: Derived from Latin Word for Chain, Catena Internet TITLE&INTRO CONSTRUCTION ANALYSIS FINALE Some History 1638, Galileo discussed the hanging-chain problem. 1690, Jacob Bernoulli published a challenge to solve the problem within 1 year. 1691, Leibniz and Johann Bernoulli published the first solutions. 1761, Johann Heinrich Lambert introduced hyperbolic functions and named them: ex + e−x ex − e−x cosh x = sinh x = 2 2 TITLE&INTRO CONSTRUCTION ANALYSIS FINALE Leibniz’s solution was presented as a classic “Ruler & Compass” construction. Paradox? The Construction is not possible because e is transcendental! And yet it is correct! It reveals analytical knowledge of the exponential function, and it depicts a hyperbolic cosine. (70 years before Lambert!) Leibniz did not publish the derivation of his construction. (It was communicated in a private letter.) And so our story begins.... TITLE&INTRO CONSTRUCTION ANALYSIS FINALE Analytic Formulation of the Catenary We can express the catenary in terms of a hyperbolic cosine: x y = a cosh . a Or in terms of exponentials: x − x e a + e a y = a · . 2 The curve is bilaterally symmetric about the y-axis, and the lowest point is at (0; a). TITLE&INTRO CONSTRUCTION ANALYSIS FINALE Leibniz’s Representation of the Catenary: A Classical Ruler & Compass Construction TITLE&INTRO CONSTRUCTION ANALYSIS FINALE The segments D and K are assumed given.
    [Show full text]
  • Differential Geometry of Curves and Surfaces 1
    DIFFERENTIAL GEOMETRY OF CURVES AND SURFACES 1. Curves in the Plane 1.1. Points, Vectors, and Their Coordinates. Points and vectors are fundamental objects in Geometry. The notion of point is intuitive and clear to everyone. The notion of vector is a bit more delicate. In fact, rather than saying what a vector is, we prefer to say what a vector has, namely: direction, sense, and length (or magnitude). It can be represented by an arrow, and the main idea is that two arrows represent the same vector if they have the same direction, sense, and length. An arrow representing a vector has a tail and a tip. From the (rough) definition above, we deduce that in order to represent (if you want, to draw) a given vector as an arrow, it is necessary and sufficient to prescribe its tail. a c b b a c a a b P Figure 1. We see four copies of the vector a, three of the vector b, and two of the vector c. We also see a point P . An important instrument in handling points, vectors, and (consequently) many other geometric objects is the Cartesian coordinate system in the plane. This consists of a point O, called the origin, and two perpendicular lines going through O, called coordinate axes. Each line has a positive direction, indicated by an arrow (see Figure 2). We denote by R the a P y a y x O O x Figure 2. The point P has coordinates x, y. The vector a has also coordinates x, y.
    [Show full text]
  • 5.8 Hyperbolic Functions 383
    5.8 Hyperbolic Functions 383 5.8 Hyperbolic Functions Develop properties of hyperbolic functions. Differentiate and integrate hyperbolic functions. Develop properties of inverse hyperbolic functions. Differentiate and integrate functions involving inverse hyperbolic functions. Hyperbolic Functions In this section, you will look briefly at a special class of exponential functions called hyperbolic functions. The name hyperbolic function arose from comparison of the area of a semicircular region, as shown in Figure 5.29, with the area of a region under a hyperbola, as shown in Figure 5.30. y y y = 1 + x2 2 2 y = 1 − x2 x x JOHANN HEINRICH LAMBERT −11−11 (1728–1777) 2 ϩ 2 ϭ Ϫ 2 ϩ 2 ϭ The first person to publish a Circle:x y 1 Hyperbola: x y 1 comprehensive study on hyperbolic Figure 5.29 Figure 5.30 functions was Johann Heinrich Lambert, a Swiss-German mathe- The integral for the semicircular region involves an inverse trigonometric (circular) matician and colleague of Euler. See LarsonCalculus.com to read function: more of this biography. 1 1 1 ␲ ͵ Ί1 Ϫ x2 dx ϭ ΄xΊ1 Ϫ x2 ϩ arcsin x ΅ ϭ Ϸ 1.571. Ϫ1 2 Ϫ1 2 The integral for the hyperbolic region involves an inverse hyperbolic function: 1 1 1 ͵ Ί ϩ 2 ϭ Ί ϩ 2 ϩ Ϫ1 Ϸ 1 x dx ΄x 1 x sinh x ΅ 2.296. Ϫ1 2 Ϫ1 This is only one of many ways in which the hyperbolic functions are similar to the trigonometric functions. Definitions of the Hyperbolic Functions REMARK The notation e x Ϫ eϪx 1 sinh x ϭ csch x ϭ , x 0 sinh x is read as “the hyperbolic 2 sinh x sine of x,” cosh x as “the e x ϩ eϪx 1 cosh x ϭ sech x ϭ hyperbolic cosine of x,” and 2 cosh x so on.
    [Show full text]
  • Curves and Paradox
    How Euler Did It by Ed Sandifer Curves and paradox October 2008 In the two centuries between Descartes (1596-1650) and Dirichlet (1805-1859), the mathematics of curves gradually shifted from the study of the means by which the curves were constructed to a study of the functions that define those curves. Indeed, Descartes' great insight, achieved around 1637, was that curves, at least the curves he knew about, had associated equations, and some properties of the curves could be revealed by studying those equations. Almost exactly 200 years later, in 1837, Dirichlet gave his famous example of a function defined on the closed interval [0, 1] that is discontinuous at every point, namely ì0ifx is rational, fx( ) = í î1ifx is irrational. The roles of the two objects had been reversed and Mathematics had become far more interested in the study of functions than in the study of curves. Euler came roughly half way between Descartes, both in years and in the evolution of mathematical ideas. He was instrumental in the early development of the modern idea of a function used the concept to lead mathematics away from its geometric foundations and replace them with analytic, i.e. symbolic manipulations, but he could not foresee how general and abstract the idea of a function could eventually become. In 1756, Euler was devoting much of his intellectual powers to using differential equations to study the world. As we saw last month, he used them to model fluid flow. A future column will be devoted to how he used differential equations to design more efficient saws.
    [Show full text]
  • Christiaan Huygens and the Problem of the Hanging Chain John Bukowski
    Christiaan Huygens and the Problem of the Hanging Chain John Bukowski John Bukowski ([email protected]) is Associate Professor and Chair of the Department of Mathematics at Juniata College in Huntingdon, Pennsylvania. He received B.S. degrees in mathematics and physics from Carnegie Mellon University and his Ph.D. in applied mathematics from Brown University. He currently serves as Governor of the Allegheny Mountain Section of the MAA. He was a 1998–1999 Project NExT Fellow (silver dot) and is now Co-Coordinator of his Section NExT program. He finds time to do mathematics when he is not busy as College Organist, choir accompanist, church organist, or piano soloist. One of his accomplishments at Juniata is his performance of a Mozart piano concerto in 2006. He and his wife Cathy Stenson (also a mathematician) have two sons, David and Daniel, who like to ask them mathematical questions. In his Discorsi [10] of 1638, Galileo wrote much about strength of materials and cross- sections of beams, and the parabola kept appearing in these contexts. After correctly instructing the reader how to draw such a curve via projectile motion, Galileo then explained,“Theothermethodofdrawingthedesiredcurve...isthefollowing:Drive two nails into a wall at a convenient height and at the same level. Over these two nails hang a light chain. This chain will assume the form of a parabola. .” If we follow Galileo’s instructions and hang such a chain, the resulting curve certainly looks like it could be a parabola. In fact, Galileo was merely stating what was commonly thought about the problem of the hanging chain at the time, as it was widely accepted in the early seventeenth century that a hanging chain did indeed take the form of a parabola.
    [Show full text]
  • Gottfried Wilhelm Leibniz, the Humanist Agenda and the Scientific Method
    3237827: M.Sc. Dissertation Gottfried Wilhelm Leibniz, the humanist agenda and the scientific method Kundan Misra A dissertation submitted in partial fulfilment of the requirements for the degree of Master of Science (Research), University of New South Wales School of Mathematics and Statistics Faculty of Science University of New South Wales Submitted August 2011 Changes completed September 2012 THE UNIVERSITY OF NEW SOUTH WALES Thesis/Dissertation Sheet Surname or Family name: Misra First name: Kundan Other name/s: n/a Abbreviation for degree as given in the University calendar: MSc School: Mathematics and Statistics Faculty: Science Title: Gottfried Wilhelm Leibniz, the humanist agenda and the scientific method Abstract 350 words maximum: Modernity began in Leibniz’s lifetime, arguably, and due to the efforts of a group of philosopher-scientists of which Leibniz was one of the most significant active contributors. Leibniz invented machines and developed the calculus. He was a force for peace, and industrial and cultural development through his work as a diplomat and correspondence with leaders across Europe, and in Russia and China. With Leibniz, science became a means for improving human living conditions. For Leibniz, science must begin with the “God’s eye view” and begin with an understanding of how the Creator would have designed the universe. Accordingly, Leibniz advocated the a priori method of scientific discovery, including the use of intellectual constructions or artifices. He defended the usefulness and success of these methods against detractors. While cognizant of Baconian empiricism, Leibniz found that an unbalanced emphasis on experiment left the investigator short of conclusions on efficient causes.
    [Show full text]