Letters on Different Subjects in Natural Philosophy, Volume 1 (Letters to a German Princess)


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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

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Of Magnitude, or Extension 7:47 Read by Elijah Fisher
Of Velocity 7:07 Read by Elijah Fisher
Of Sound, and Its Velocity 7:52 Read by Elijah Fisher
Of Consonance and Dissonance 6:28 Read by Elijah Fisher
Of Unison and Octaves 8:10 Read by Elijah Fisher
Of Other Consonances 9:14 Read by Cbteddy
Of the Twelve Tones of the Harpsichord 13:19 Read by Cbteddy
Of the Pleasure Derived from Fine Music 5:55 Read by Cbteddy
Compression of the Air 7:23 Read by prajak
Rarefaction and Elasticity of the Air 8:16 Read by prajak
Gravity of the Air 7:01 Read by prajak
Of the Atmosphere, and the Barometer 6:18 Read by Elijah Fisher
Of Air-Guns, and the Compression of Air in Gunpowder 6:43 Read by Elijah Fisher
The Effect Produced by Heat and Cold on All Bodies, and Of, the Pyrometer and Thermometer 5:31 Read by Elijah Fisher
Changes Produced in the Atmosphere by Heat and Cold 7:48 Read by Elijah Fisher
The Cold Felt on High Mountains and at Great Depths Accounted For 7:25 Read by Elijah Fisher
Of Light, and the Systems of Descartes and Newton 6:54 Read by Bonnie de Lyons
Difficulties Attending the System of Emanation 6:36 Read by Bonnie de Lyons
A Different System Respecting the Nature of Rays and of Light Proposed 7:31 Read by Bonnie de Lyons
Of the Propagation of Light 6:42 Read by Bonnie de Lyons
Digression on the Distances of the Heavenly Bodies, and on the Nature of the Sun and His Rays 6:15 Read by czandra
Elucidations on the Nature of Luminous Bodies, and Their Difference from Opaque Bodies Illuminated 7:16 Read by Verla Viera
How Opaque Bodies Become Visible Newton's System of the Reflection of Rays Proposed 8:34 Read by Jayjaysil
Examination and Refutation of Newton's System 11:36 Read by Emanuela
A Different Explanation of the Manner in Which Opaque Bodies Illuminated Become Visible 7:44 Read by Emanuela
Continuation of the Same Subject 8:50 Read by Emanuela
Conclusion: Clearness and Colour of Opaque Bodies Illuminated 9:37 Read by Emanuela
Nature of Colours in Particular 6:28 Read by czandra
Transparency of Bodies Relative to the Transmission of Rays 8:32 Read by Elijah Fisher
Of the Transmission of Rays of Light Through Transparent Mediums, and Their Refraction 8:04 Read by Elijah Fisher
Refraction of Rays of Different Colours 7:14 Read by Elijah Fisher
Of the Azure Colour of the Heavens 8:54 Read by czandra
Of Rays Issuing from a Distant Luminous Point, and of the Visual Angle 6:34 Read by Elijah Fisher
Of the Assistance Which Judgment Lends to Vision 6:43 Read by Elijah Fisher
Explanation of Certain Phenomena Relative to Optics 7:29 Read by Elijah Fisher
Of Shadow 7:16 Read by Elijah Fisher
Of Catoptrics, and the Reflection of Rays from Plain Mirrors 8:24 Read by Elijah Fisher
Reflection of Rays from Convex and Concave Mirrors Burning Mirrors 8:04 Read by Elijah Fisher
Of Dioptrics 8:36 Read by Elijah Fisher
Continuation of Burning — Glasses, and Their Focus 7:12 Read by Elijah Fisher
Of Vision, and the Structure of the Eye 5:24 Read by Elijah Fisher
Continuation Wonders Discoverable in the Structure of the Eye 6:07 Read by Elijah Fisher
Further Continuation Astonishing Difference Between the Eye of an Animal and the Artificial Eye, or Camera Obscura 6:44 Read by Elijah Fisher
Perfections Discoverable in the Structure of the Eye 4:40 Read by Elijah Fisher
Of Gravity, Considered as a General Property of Body 6:58 Read by Elijah Fisher
Continuation of Specific Gravity 6:55 Read by Elijah Fisher
Terms Relative to Gravity and Their True Import 6:29 Read by Elijah Fisher
Reply to Certain Objections to the Erath's Spherical Figure, Derived from Gravity 6:17 Read by Jayjaysil
True Direction and Action of Gravity Relatively to the Earth 6:52 Read by Verla Viera
Different Action of Gravity with Respect to Certain Countries and Distances from the Centre of the Earth 7:57 Read by Verla Viera
Gravity of the Moon 5:33 Read by Verla Viera
Discovery of Universal Gravitation by Newton 9:08 Read by SirRoni
Continuation of the Mutual Attraction of the Heavenly Bodies 9:18 Read by prajak
Different Sentiments of Philosophers Respecting Universal Gravitation the Attractionists 7:04 Read by prajak
Power by Which the Heavenly Bodies an Mutually Attracted 4:08 Read by prajak
The Same Subject Continued 6:41 Read by prajak
The Same Subject Continued 6:37 Read by prajak
Motion of the Heavenly Bodies Method of Determining It by the Laws of Universal Gravitation 4:56 Read by Cbteddy
System of the Universe 6:40 Read by Cbteddy
The Same Subject Continued 5:29 Read by Cbteddy
Small Irregularities in the Motions of the Planets, Caused by Their Mutual Attraction 5:59 Read by Cbteddy
Description of the Flux and Reflux of the Sea 6:45 Read by Belinda Mc
Different Opinions of Philosophers Respecting the Flux and Reflux of the Sea 6:22 Read by Belinda Mc
Explanation of the Flux and Reflux, from the Attractive Power of the Moon 5:33 Read by Verla Viera
The Same Subject Continued 5:06 Read by Verla Viera
The Same Subject Continued 6:17 Read by Verla Viera
The Same Subject Continued 6:15 Read by Verla Viera
More Particular Account of the Dispute Respecting Universal Gravitation 7:05 Read by Ty Lasky
Nature and Essence of Bodies or Extension, Mobility, and Impenetrability of Body 7:33 Read by ShrimpPhish
Impenetrability of Bodies 5:40 Read by ShrimpPhish
Of the Motion of Bodies, Real and Apparent 8:16 Read by ShrimpPhish
Of Uniform, Accelerated, and Retarded Motion 12:33 Read by SirRoni
Principal Law of Motion and Rest Disputes of Philosophers on the Subject 8:02 Read by jenno
Of the Inertia of Bodies of Powers 7:47 Read by jenno
Changes Which May Take Place in the State of Bodies 8:05 Read by elizabethhousworth
System of the Monads of Wolff 8:09 Read by elizabethhousworth
Origin and Nature of Powers 7:11 Read by Cajucom
The Same Subject Principle of the Least Possible Action 7:16 Read by jenno
On the Question, are There Any Other Species of Powers? 7:40 Read by jenno
Of the Nature of Spirits 5:12 Read by Owlivia
Of the Union Between the Soul and the Body 6:32 Read by Owlivia
Different Systems Relative to This Subject 6:49 Read by Owlivia
Examination of the System of Pre-Established Harmony an Objection to It 7:02 Read by Owlivia
Another Objection 6:32 Read by Owlivia
Of the Liberty of Spirits, and a Reply to Objections Against Liberty 6:40 Read by Owlivia
Tne Same Subject Continued 7:17 Read by Owlivia
Influence of the Liberty of Spirits Upon Events 7:45 Read by Owlivia
Of Events Natural, Supernatural, and Moral 7:03 Read by Owlivia
Of the Question Respecting the Best World Possible; and of the Origin of Evil 8:23 Read by Owlivia
Connexion of the Preceding Considerations with Religion Reply to the Objections of the Philosophical Systems Against Prayer 6:16 Read by Owlivia
The Liberty of Intelligent Beings in Harmony with the Doctrines of the Christian Religion 5:52 Read by Owlivia
Elucidation Respecting the Nature of Spirits 8:14 Read by Owlivia
The Subject Continued Reflections on the State of Souls After Death 9:03 Read by Owlivia
Considerations on the Action of the Soul Upon the Body, and of the Body Upon the Soul 8:00 Read by Owlivia
Of the Faculties of the Soul, and of Judgment 8:58 Read by Owlivia
Conviction of the Existence of What We Perceive by the Senses of the Idealists, Egotists, and Materialists 8:27 Read by elizabethhousworth
Refutation of the Idealists 8:22 Read by Constandina Sharpe
The Faculty of Perceiving, Reminiscence, Memory, and Attention Simple and Compound Ideas 7:54 Read by jenno
Division of Ideas into Clear and Obscure, Distinct and Confused of Distraction 7:07 Read by jenno
Of the Abstraction of Notions Notions General and Individual: of Genus and Species 8:00 Read by jenno
Of Language; Its Nature, Advantages, and Necessity, in Order to the Communication of Thought, and the Cultivation of Knowledge 8:39 Read by Andrew Mauls Byron
Of the Perfections of a Language Judgment and Nature of Propositions, Affirmative and Negative, Universal or Particular 7:59 Read by Andrew Mauls Byron
Of Syllogisms, and Their Different Forms When the First Proposition is Universal 9:31 Read by MaryAnn
Different Forms of Syllogisms Whose First Proposition is Particular 9:08 Read by MaryAnn
Analysis of Some Syllogisms 7:15 Read by MaryAnn
Different Figures and Modes of Syllogisms 11:03 Read by MaryAnn
Observations and Reflections on the Different Modes of Syllogism 6:53 Read by MaryAnn
Hypothetical Propositions, and Syllogisms Constructed of Them 8:48 Read by SirRoni
Of the Impression of Sensations on the Soul 7:11 Read by jenno
Of the Origin and Permission of Evil, and of Sin 9:30 Read by SirRoni
Of Moral and Physical Evil 6:35 Read by Larry Wilson
Reply to Complaints of the Existence of Physical Evil 6:14 Read by Larry Wilson
The Real Destination of Man Usefulness and Necessity of Adversity 5:16 Read by Larry Wilson
Of True Happiness. Conversion of Sinners. Reply to Objections on the Subject 6:32 Read by Larry Wilson
The True Foundation of Human Knowledge Sources of Truth, and Classes of Information Derived from It 5:29 Read by Larry Wilson