Letters on Different Subjects in Natural Philosophy, Volume 1 (Letters to a German Princess)
Leonhard Euler
115 chapters · 14 h 8 min · English
Read by Elijah Fisher, Cbteddy, prajak, Bonnie de Lyons, czandra, Verla Viera and others
Mathematics · Astronomy, Physics & Mechanics
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The Letters of Euler to a German Princess have acquired over all Europe a celebrity to which the reputation of the Author, the choice and importance of the several subjects, and the clearness of elucidation justly entitle them. They have deservedly been considered as a treasury of science, adapted to the purposes of every common seminary of learning. They may be studied to advantage without much previous elementary knowledge; they convey accurate ideas respecting a variety of objects, highly interesting in themselves, or calculated to excite a laudable curiosity; they inspire a proper taste for the sciences, and for that sound philosophy which, supported by science, and never losing sight of her cautious, steady, methodical advances, runs no risk of perplexing or misleading the attentive student. - Summary by Nicolas de Condorcet
Chapters
1 Of Magnitude, or Extension 8 min 2 Of Velocity 7 min 3 Of Sound, and Its Velocity 8 min 4 Of Consonance and Dissonance 6 min 5 Of Unison and Octaves 8 min 6 Of Other Consonances 9 min 7 Of the Twelve Tones of the Harpsichord 13 min 8 Of the Pleasure Derived from Fine Music 6 min 9 Compression of the Air 7 min 10 Rarefaction and Elasticity of the Air 8 min 11 Gravity of the Air 7 min 12 Of the Atmosphere, and the Barometer 6 min 13 Of Air-Guns, and the Compression of Air in Gunpowder 7 min 14 The Effect Produced by Heat and Cold on All Bodies, and Of, the Pyrometer and Thermometer 6 min 15 Changes Produced in the Atmosphere by Heat and Cold 8 min 16 The Cold Felt on High Mountains and at Great Depths Accounted For 7 min 17 Of Light, and the Systems of Descartes and Newton 7 min 18 Difficulties Attending the System of Emanation 7 min 19 A Different System Respecting the Nature of Rays and of Light Proposed 8 min 20 Of the Propagation of Light 7 min 21 Digression on the Distances of the Heavenly Bodies, and on the Nature of the Sun and His Rays 6 min 22 Elucidations on the Nature of Luminous Bodies, and Their Difference from Opaque Bodies Illuminated 7 min 23 How Opaque Bodies Become Visible Newton's System of the Reflection of Rays Proposed 9 min 24 Examination and Refutation of Newton's System 12 min 25 A Different Explanation of the Manner in Which Opaque Bodies Illuminated Become Visible 8 min 26 Continuation of the Same Subject 9 min 27 Conclusion: Clearness and Colour of Opaque Bodies Illuminated 10 min 28 Nature of Colours in Particular 6 min 29 Transparency of Bodies Relative to the Transmission of Rays 9 min 30 Of the Transmission of Rays of Light Through Transparent Mediums, and Their Refraction 8 min 31 Refraction of Rays of Different Colours 7 min 32 Of the Azure Colour of the Heavens 9 min 33 Of Rays Issuing from a Distant Luminous Point, and of the Visual Angle 7 min 34 Of the Assistance Which Judgment Lends to Vision 7 min 35 Explanation of Certain Phenomena Relative to Optics 7 min 36 Of Shadow 7 min 37 Of Catoptrics, and the Reflection of Rays from Plain Mirrors 8 min 38 Reflection of Rays from Convex and Concave Mirrors Burning Mirrors 8 min 39 Of Dioptrics 9 min 40 Continuation of Burning: Glasses, and Their Focus 7 min 41 Of Vision, and the Structure of the Eye 5 min 42 Continuation Wonders Discoverable in the Structure of the Eye 6 min 43 Further Continuation Astonishing Difference Between the Eye of an Animal and the Artificial Eye, or Camera Obscura 7 min 44 Perfections Discoverable in the Structure of the Eye 5 min 45 Of Gravity, Considered as a General Property of Body 7 min 46 Continuation of Specific Gravity 7 min 47 Terms Relative to Gravity and Their True Import 6 min 48 Reply to Certain Objections to the Erath's Spherical Figure, Derived from Gravity 6 min 49 True Direction and Action of Gravity Relatively to the Earth 7 min 50 Different Action of Gravity with Respect to Certain Countries and Distances from the Centre of the Earth 8 min 51 Gravity of the Moon 6 min 52 Discovery of Universal Gravitation by Newton 9 min 53 Continuation of the Mutual Attraction of the Heavenly Bodies 9 min 54 Different Sentiments of Philosophers Respecting Universal Gravitation the Attractionists 7 min 55 Power by Which the Heavenly Bodies an Mutually Attracted 4 min 56 The Same Subject Continued 7 min 57 The Same Subject Continued 7 min 58 Motion of the Heavenly Bodies Method of Determining It by the Laws of Universal Gravitation 5 min 59 System of the Universe 7 min 60 The Same Subject Continued 5 min 61 Small Irregularities in the Motions of the Planets, Caused by Their Mutual Attraction 6 min 62 Description of the Flux and Reflux of the Sea 7 min 63 Different Opinions of Philosophers Respecting the Flux and Reflux of the Sea 6 min 64 Explanation of the Flux and Reflux, from the Attractive Power of the Moon 6 min 65 The Same Subject Continued 5 min 66 The Same Subject Continued 6 min 67 The Same Subject Continued 6 min 68 More Particular Account of the Dispute Respecting Universal Gravitation 7 min 69 Nature and Essence of Bodies or Extension, Mobility, and Impenetrability of Body 8 min 70 Impenetrability of Bodies 6 min 71 Of the Motion of Bodies, Real and Apparent 8 min 72 Of Uniform, Accelerated, and Retarded Motion 13 min 73 Principal Law of Motion and Rest Disputes of Philosophers on the Subject 8 min 74 Of the Inertia of Bodies of Powers 8 min 75 Changes Which May Take Place in the State of Bodies 8 min 76 System of the Monads of Wolff 8 min 77 Origin and Nature of Powers 7 min 78 The Same Subject Principle of the Least Possible Action 7 min 79 On the Question, are There Any Other Species of Powers? 8 min 80 Of the Nature of Spirits 5 min 81 Of the Union Between the Soul and the Body 7 min 82 Different Systems Relative to This Subject 7 min 83 Examination of the System of Pre-Established Harmony an Objection to It 7 min 84 Another Objection 7 min 85 Of the Liberty of Spirits, and a Reply to Objections Against Liberty 7 min 86 Tne Same Subject Continued 7 min 87 Influence of the Liberty of Spirits Upon Events 8 min 88 Of Events Natural, Supernatural, and Moral 7 min 89 Of the Question Respecting the Best World Possible; and of the Origin of Evil 8 min 90 Connexion of the Preceding Considerations with Religion Reply to the Objections of the Philosophical Systems Against Prayer 6 min 91 The Liberty of Intelligent Beings in Harmony with the Doctrines of the Christian Religion 6 min 92 Elucidation Respecting the Nature of Spirits 8 min 93 The Subject Continued Reflections on the State of Souls After Death 9 min 94 Considerations on the Action of the Soul Upon the Body, and of the Body Upon the Soul 8 min 95 Of the Faculties of the Soul, and of Judgment 9 min 96 Conviction of the Existence of What We Perceive by the Senses of the Idealists, Egotists, and Materialists 8 min 97 Refutation of the Idealists 8 min 98 The Faculty of Perceiving, Reminiscence, Memory, and Attention Simple and Compound Ideas 8 min 99 Division of Ideas into Clear and Obscure, Distinct and Confused of Distraction 7 min 100 Of the Abstraction of Notions Notions General and Individual: of Genus and Species 8 min 101 Of Language; Its Nature, Advantages, and Necessity, in Order to the Communication of Thought, and the Cultivation of Knowledge 9 min 102 Of the Perfections of a Language Judgment and Nature of Propositions, Affirmative and Negative, Universal or Particular 8 min 103 Of Syllogisms, and Their Different Forms When the First Proposition is Universal 10 min 104 Different Forms of Syllogisms Whose First Proposition is Particular 9 min 105 Analysis of Some Syllogisms 7 min 106 Different Figures and Modes of Syllogisms 11 min 107 Observations and Reflections on the Different Modes of Syllogism 7 min 108 Hypothetical Propositions, and Syllogisms Constructed of Them 9 min 109 Of the Impression of Sensations on the Soul 7 min 110 Of the Origin and Permission of Evil, and of Sin 10 min 111 Of Moral and Physical Evil 7 min 112 Reply to Complaints of the Existence of Physical Evil 6 min 113 The Real Destination of Man Usefulness and Necessity of Adversity 5 min 114 Of True Happiness. Conversion of Sinners. Reply to Objections on the Subject 7 min 115 The True Foundation of Human Knowledge Sources of Truth, and Classes of Information Derived from It 5 min
