‎Message aux Pays Libres ‎

‎ Message to the Free Countries, Didier, New York, ,1942 ,Gd in-8, br., Edition originale, tirage limité à 1000 ex. num. sur papier spécial.avec jaquette en cristal décorée de toiles d'arraignée, exemplaire no 69 sur 1000 ‎

‎Ray AC7* ‎

‎Trois Américaines à Paris: Jacqueline Bouvier Kennedy Susan Sontag Angela Davis‎

‎Gallimard 2026 384 pages 15 6x22 4x2 6cm. 2026. Broché. 384 pages.‎

‎bon état bonne tenue intérieur propre‎

‎On the aberration of compound lenses and object-glasses. Read March 22, 1821.‎

‎London, W. Bulmer and W. Nicol, 1821. 4to. No wrappers as extracted from ""Philosophical Transactions"" 1821 - Part I. With titlepage to Part I. Pp. 222-267 a. 1 engraved plate. Verso of titlepage with 2 stamps.‎

‎First appearance of this importent paper in optical theory in which Herschel described how to free lenses from the aberration for two axis points, one of which is infinitely distant. It is known as Herschel's condition. ""Sir John Herschel gave the condition which must be satisfied in order that a symmetrical optical system, free from spherical aberration for two conjugate axial points, may also be free from spherical aberration for two neighbouring and conjugate points upon the axis of the system" but Herschel's condition applies only to first order aberration, i.e. to aberration depending upon the cube of the inclination of the ray to the axis. Abbe shewed, later, that this condition could be included in a wider result, viz. that the spherical aberration, supposed zero, is stationary for axial variations provided that the incident and emergent rays for two conjugate axial points, associated with modified magnification m, satisfy the relation. (G.C. Stewart)‎

‎On certain Improvements on Photographic Processes described in a former Communication, and on the Parathermic Rays of the Solar Spectrum. Received November 17, - Read November 17, 1842.‎

‎(London, Richard and John E., Taylor, 1843. 4to. No wrappers as extracted from ""Philosophical Transactions"" 1843 - Part I. Pp. 1-6.‎

‎First appearance of a pioneer-paper in the history of early photography, as Herschel here for the first time describes his discovery of the iron printing process with ammonio-citrate of iron by both methods, namely with blue lines on a white background and white lines on a blue ground.‎

‎On the Direction and Velocity of the Motion of the Sun, and the Solar System. Read May 16, 1805.‎

‎(London, W. Bulmer and Co., 1805). 4to. No wrappers as extracted from ""Philosophical Transactions"" 1805 - Part II. Pp. 233-256 a. 1 engraved plate, folded. Clean and fine.‎

‎First printing of an importent paper in cosmology in which Herschel's by analyzing a large number of stars, believed that he could explain the regularities he observed by assuming that the sun itself was moving toward a point in the consellation of Hercules. ""Just as Copernicus had detroned the earth as the motionless center of the universe, so Herschel detroned the sun.""(Asimov). - In this paper he tries to estimate the speed of the sun's motion.In a memoir published in 1783 Herschel had been occupied with the possibility that the sun was moving relative to the stars. ""More than 20 years later (1805, in the paper offered) Herschel took up the question again, using six of the brightest stars in a collection of the proper motions of 36 published by Maskelyne in 1790, which were much more reliable than any earlier ones, and employing more elaborate processes of calculation" again the apex was placed in the constellation of Hercules, though at a distance of nearly 30 degr. from the position given in 1783. Herschel's results were avowedly to a large extent speculative and were received by contemporary astronomers with a large measure of distrust" but a number of far more elaborate modern investigations of the same subject have confirmed the general correctness of his work.""(Berry ""A Short History of Astronomy"", p. 346.).‎

‎On the Direction and Velocity of the Motion of the Sun, and the Solar System. Read May 16, 1805.‎

‎(London, W. Bulmer and Co., 1805). 4to. No wrappers as extracted from ""Philosophical Transactions"" 1805 - Part II. Pp. 233-256 a. 1 engraved plate, folded. Clean and fine.‎

‎First printing of an importent paper in cosmology in which Herschel's by analyzing a large number of stars, believed that he could explain the regularities he observed by assuming that the sun itself was moving toward a point in the consellation of Hercules. ""Just as Copernicus had detroned the earth as the motionless center of the universe, so Herschel detroned the sun.""(Asimov). - In this paper he tries to estimate the speed of the sun's motion.In a memoir published in 1783 Herschel had been occupied with the possibility that the sun was moving relative to the stars. ""More than 20 years later (1805, in the paper offered) Herschel took up the question again, using six of the brightest stars in a collection of the proper motions of 36 published by Maskelyne in 1790, which were much more reliable than any earlier ones, and employing more elaborate processes of calculation" again the apex was placed in the constellation of Hercules, though at a distance of nearly 30 degr. from the position given in 1783. Herschel's results were avowedly to a large extent speculative and were received by contemporary astronomers with a large measure of distrust" but a number of far more elaborate modern investigations of the same subject have confirmed the general correctness of his work.""(Berry ""A Short History of Astronomy"", p. 346.).‎

‎Account of the Changes that have happened, during the last Twenty-five Years, in the relative Situation of Double-stars" with an Investigation of the Cause to which they are owing. Read June 9, 1803.‎

‎(London, Bulwer and Co., 1803). 4to. Without wrappers as extracted from ""Philosophical Transactions of the Royal Society of London."" Year 1803-Part II. Pp. 339-382 and 2 engraved plates.‎

‎First appearance of a fundamental paper in cosmology and physics as it contains the first observational data to support that Newton's dynamical laws holds outside the solar system. Herschel shows here that the circulating motions of double-stars were under gravitational forces. Until then the validity of the law of gravity was only established within the solar system. Now, a century after the establishment of the law, it was traced out in the motion of incredibly distant stars and the theory first truly earned its title of Universal. The exact proof of the mutual gravitation of the double-stars was only obtained five years after Herschel's death, when the motions of the stars were more precisely dtermined.One of the most notable of Herschel's discoveries of double-stars, binary stars. A first cataloque of such pairs was published early in 1782 and contained 269, of which 227 were new discoveries. ""Twenty years after the publication of his first cataloque Herschel was of Michell's opinion - Michell had expressed the opinion that the odds in favour of a physical relation between the members of herschel's newly discovered double stars were ""beyond arithmetic"" - but was able to support it by evidence of an entirely novel and much more direct character. A series of observations of Castor, presented in two papers in the ""Philosophical Transaction"" in 1803 (the paper offered here) and 1804, which were fortunately supplemented by an observation of Bradley's in 1759, had shewn a progressive alteration in the direction of the line joining its two components, of such a character as to leave no doubt that the two stars were revolving round one another"" and there were five oher cases in which a similar motion was observed...it was shown that the double-star was really formed by a connected pair of stars near enough to influence one another's mortion.""(Berry in ""A Short History of Astronomy"" pp. 342-43).‎

‎Account of the Changes that have happened, during the last Twenty-five Years, in the relative Situation of Double-stars" with an Investigation of the Cause to which they are owing. Read June 9, 1803. (+) Continuation of an Account ofthe Changes that h...‎

‎(London, Bulwer and Co., 1803 a. 1804). 4to. Without wrappers as extracted from ""Philosophical Transactions of the Royal Society of London."" Year 1803-Part II. Pp. 339-382 and 2 engraved plates. a. Year 1804-Part II. Pp. 353-384 a. 1 engraved plate. Light browning to a few margins. 2 plates with scattered brownspots, otherwise clean and wide-margined.‎

‎First appearance of these fundamental paper in cosmology and physics as they contains the FIRST OBSERVATIONAL DATA TO SUPPORT THAT NEWTON'S DYNAMICAL LAWS HOLDS OUTSIDE THE SOLAR SYSTEM. Herschel shows here that the circulating motions of double-stars were under gravitational forces. Until then the validity of the law of gravity was only established within the solar system. Now, a century after the establishment of the law, it was traced out in the motion of incredibly distant stars and the theory first truly earned its title of Universal. The exact proof of the mutual gravitation of the double-stars was only obtained five years after Herschel's death, when the motions of the stars were more precisely dtermined.One of the most notable of Herschel's discoveries of double-stars, binary stars. A first cataloque of such pairs was published early in 1782 and contained 269, of which 227 were new discoveries. ""Twenty years after the publication of his first cataloque Herschel was of Michell's opinion - Michell had expressed the opinion that the odds in favour of a physical relation between the members of Herschel's newly discovered double stars were ""beyond arithmetic"" - but was able to support it by evidence of an entirely novel and much more direct character. A series of observations of Castor, presented in two papers in the ""Philosophical Transaction"" in 1803 and 1804 (the paperS offered ), which were fortunately supplemented by an observation of Bradley's in 1759, had shewn a progressive alteration in the direction of the line joining its two components, of such a character as to leave no doubt that the two stars were revolving round one another"" and there were five oher cases in which a similar motion was observed...it was shown that the double-star was really formed by a connected pair of stars near enough to influence one another's mortion.""(Berry in ""A Short History of Astronomy"" pp. 342-43).‎

‎Experiments for ascertaining how far Telescopes will enable us to determine very small Angles, and to distinguish the real from the spurious Diameters of celestial and terrestrial Objects: with an Application of the Result ofthese Experiments to a ser...‎

‎(London, W. Bulmer and Co., 1805). 4to. No wrappers as extracted from ""Philosophical Transactions"" 1805 - Part I. Pp. 31-64 and 1 engraved plate. Clean and fine.‎

‎First appearance of an importent paper, founding the metric of interstellar space.It was the contemporous discoveries of the first minor planets, ceres in 1801, Pallas in 1802 and Juno in 1803, that prompted Herschel to investigate the origin of the spurious diameters of stars. ""Were their apparent diameters as real as those of planets or spurious as for stars? To address this question Herschel conducted an extensive series of experiments in his garden in Slough, examining through his telescope small globules of differing sizes and materials placed in a tree some 800 ft (ca. 244 m) away (Herschel 1805). His observations showed that for the smallest globules the diameters were all spurious and all of the same size. Furthermore, he found that, if just the inner part of the aperture of the telescope were used, the spurious diameters, whether of globules or of stars, were larger. If the whole aperture was employed, the diameters were smaller, and if only an outer annular aperture was used the diameters were smaller still. This experimental discovery that unfilled apertures can be used to obtain high angular resolution remains today the essential basis for interferometric imaging in astronomy (in particular Aperture Masking Interferometry). The theoretical justification of this result came with Airy's analysis of the diffraction pattern of a circular aperture 30 years later (Airy 1835), and it took a further 30 years before the idea of using multiple apertures was developed. In an early study the Reverend W. R. Dawes noted that he had frequently found great advantage from the use of a perforated whole aperture' and that when observing Venus this produced a central image of the planet perfectly colourless, and very sharply dened' (Dawes 1866). But it was left to Fizeau, in his submission to the Commission for the Prix Bordin the following year, to remark on une relation remarquable et n´ecessaire entre la dimension des franges et celle de la source lumineuse' and suggest that by using an interferometric combination of light from two separated slits il deviendra possible d'obtenir quelques donn´ees nouvelles sur les diametres angulaires de ces astres' (Fizeau 1868).""‎

‎Experiments for ascertaining how far Telescopes will enable us to determine very small Angles, and to distinguish the real from the spurious Diameters of celestial and terrestrial Objects: with an Application of the Result ofthese Experiments to a ser...‎

‎(London, W. Bulmer and Co., 1805). 4to. No wrappers as extracted from ""Philosophical Transactions"" 1805 - Part I. Pp. 31-64 and 1 engraved plate. Clean and fine.‎

‎First appearance of an importent paper, founding the metric of interstellar space.It was the contemporous discoveries of the first minor planets, ceres in 1801, Pallas in 1802 and Juno in 1803, that prompted Herschel to investigate the origin of the spurious diameters of stars. ""Were their apparent diameters as real as those of planets or spurious as for stars? To address this question Herschel conducted an extensive series of experiments in his garden in Slough, examining through his telescope small globules of differing sizes and materials placed in a tree some 800 ft (ca. 244 m) away (Herschel 1805). His observations showed that for the smallest globules the diameters were all spurious and all of the same size. Furthermore, he found that, if just the inner part of the aperture of the telescope were used, the spurious diameters, whether of globules or of stars, were larger. If the whole aperture was employed, the diameters were smaller, and if only an outer annular aperture was used the diameters were smaller still. This experimental discovery that unfilled apertures can be used to obtain high angular resolution remains today the essential basis for interferometric imaging in astronomy (in particular Aperture Masking Interferometry). The theoretical justification of this result came with Airy's analysis of the diffraction pattern of a circular aperture 30 years later (Airy 1835), and it took a further 30 years before the idea of using multiple apertures was developed. In an early study the Reverend W. R. Dawes noted that he had frequently found great advantage from the use of a perforated whole aperture' and that when observing Venus this produced a central image of the planet perfectly colourless, and very sharply dened' (Dawes 1866). But it was left to Fizeau, in his submission to the Commission for the Prix Bordin the following year, to remark on une relation remarquable et n´ecessaire entre la dimension des franges et celle de la source lumineuse' and suggest that by using an interferometric combination of light from two separated slits il deviendra possible d'obtenir quelques donn´ees nouvelles sur les diametres angulaires de ces astres' (Fizeau 1868).""‎

‎Untersuchungen über die wärmende und die erleuchtende Kraft der farbigen Sonnenstrahlen Versuch über die nichht-sichbaren Strahlen der Sonne und deren Brechbarkeit" und Einrichtung grosser Teleskope zu Sonnenbeobachtungen.‎

‎Halle, Rengerschen Buchhandlung, 1801. Without wrappers as published in ""Annalen der Physik. Herausgegeben von Ludwig Wilhelm Gilbert"", Bd. 7, Zweites Stück. The entire issue offered (=Heft 2). Pp. 137-264 a. 2 folded engraved plates. Herschels papers: pp. 137-156. The plate depicts Herschel's experimental arrangements.‎

‎First appearance in German of Herschel's epochal announcement of his discovery of infrared light in 1800. This was the first time that a form of light beyond visible light had been detected. The paper offered is the German translation of the main parts of Herschel's paper ""An Investigation of the Powers of Prismatic Colours to Heat and Illuminate Objects"".""In 1800 he tested various portions of the sun's spectrum by thermometer to see if he could find interesting differences in the amount of heat the different colors delivered. He did, but in a rather unexpected way, for he found that the temperature rise was highest in no color at all, at a spot beyond the red end of the spectrum. He concluded that the sunlight contained invisible light beyond the red. This is now called infrared radiation. The following year Ritter was to extend the visible spectrum in the other direction.""(Asimov).Parkinson ""Breakthroughs"" 1800 P.‎

‎Astronomical Observations relating to the Construction of the Heavens, arranged for the Purpose of a critical Examination, the Result of which appears to throw some new Light upon the Organization of the celestial Bodies. Read June 20, 1811. (+)Astron...‎

‎(London, W. Bulmer and Co., 1811 a.1814). 4to. No wrappers as extracted from ""Philosophical Transactions"" Year 1811-Part II. 269-336 and 2 engraved plates showing the shapes of 42 nebulae and star-clusters. And 1814 - Part I. Pp. 248-84 a. 1 engraved plate. Both fine and clean.‎

‎First appearance of two milestone papers in cosmology in which Herschel demonstrates the irregular distribution of the stars in space, and ""for the first time recognized that the clusters in and near the Milky Way really belonged to it, and were not independent systems that happened to lie in the same direction as seen by us.""(Berry, Short History of Astronomy, p. 340).""In 1811 and 1814 (the papers offered) he published a complete theory of a possible process wherby the shining fluid consisting a diffused nebula might gradually condense - the denser portions of it being centres of attraction - first into a denser nebula or compressed star cluster, then into one or more nebulous stars, lastly into a single star or group of stars. Every supposed stage in this process was abundantly illustrated from records of actual nebulae and clusters which he had observed.""(Berry).""Illustrated with many examples at every stage, these papers (1811 a. 1814) showed brilliantly how dynamic changes can be inferred from virtually static evidence"" and Herschel concluded by characterizing the Milky Way in its present stage of dissolution as ""this mysterious chronometer"". (DSB VI, p. 333). A paper by Henry Kater attached: ""Further Experiments on the Light of the Cassegrainian telescope compared with that of the Georgian"". 1814. Pp. 231-247.‎

‎Astronomical Observations relating to the Construction of the Heavens, arranged for the Purpose of a critical Examination, the Result of which appears to throw some new Light upon the Organization of the celestial Bodies. Read June 20, 1811.‎

‎(London, W. Bulmer and Co., 1811). 4to. No wrappers as extracted from ""Philosophical Transactions"" Year 1811-Part II. With titlepage to vol. II. 269-336 and 2 engraved plates showing the shapes of 42 nebulae and star-clusters. Some brownspots to margins of the plates, otherwise clean and wide-margined.‎

‎First appearance of a milestone papers in cosmology in which Herschel demonstrates the irregular distribution of the stars in space, and ""for the first time recognized that the clusters in and near the Milky Way really belonged to it, and were not independent systems that happened to lie in the same direction as seen by us.""(Berry, Short History of Astronomy, p. 340).""In 1811 and 1814 he published a complete theory of a possible process wherby the shining fluid consisting a diffused nebula might gradually condense - the denser portions of it being centres of attraction - first into a denser nebula or compressed star cluster, then into one or more nebulous stars, lastly into a single star or group of stars. Every supposed stage in this process was abundantly illustrated from records of actual nebulae and clusters which he had observed.""(Berry).‎

‎Observations tending to investigate the Nature of the Sun, in order to find the Causes or Symptoms of its variable Emission of Light and Heat" with Remarks on the Use that may possibly be drawn from Solar Observations. Read April 16, 1801.‎

‎(London, W. Bulmer and Co., 1801). 4to. No wrappers as extracted from ""Philosophical Transactions"" 1801 - Part I. Pp. 265-318 and 2 folded engraved plates. Wide-margined. A few small marginal brownspots.‎

‎First appearance of an remarkable paper containing an extensive set of observations on the sunspots intermingled with what Herschel called ""ideas that obtruded themselves"" at the time of observation.""Herschel's interest in the sun was naturally stimulated by the realization that, of all the stars, it alone is close enough for detailled examination. he was aware of the various existing theories of the physical constitution of the sun. In a long paper published in 1795 he mentions some of them before his own observations...In 1801, in a second long paper (the paper offered here) in which he arranged his observations according to relevant physical questions, he modified his earlier account of the sun to include in its constitution an interior layer of dark clouds not unlike our own, this layer serving to shield the solar inhabitants from the exterior, luminous layer.‎

‎LE RECIT DE LA CREATION: Miniatures de la Bibliothèque Vaticane‎

‎Herscher 1995 23x1 4x24 6cm. 1995. Broché.‎

‎John Wayne Movie Poster At Auction‎

‎ 2004 Juin 2004 - Catalogue d'enchères - In-4 broché - Sans pagination - Couverture illustrée - Nombreuses illustrations (affiches de cinéma) en couleur‎

‎Bon état ‎

‎L'Amérique expliquée au monde entier‎

‎Stock 2026 3x22x14cm. 2026. Broché.‎

‎tranches légèrement fânées‎

‎The Jews in Polish Culture (Jewish Lives)‎

‎Northwestern University Press 1988 266 pages 14 99x2 29x22 61cm. 1988. Broché. 266 pages.‎

‎Bon Etat tranche un peu ternie intérieur propre‎

‎Versuche zur Feststellung einer oberen Grenze für die kinetische Energie der elektrischen Strömung.‎

‎Leipzig, Johann Ambrosius Barth, 1880. Without wrappers as issued in ""Annalen der Physik und Chemie. Hrsg. von G. Wiedemann."", Neue Folge Bd. 10, 7. Heft With Titlepage to vol. 10.. Pp. 337-512 a. 1 folded plate, (entire issue offered ""Heft"" 7). Hertz's paper: pp. 414-448.‎

‎First printing of Hertz's first paper by which he won the Philosophical Faculty Prize (Berlin) in 1879, earning a medal, a first publication in Annalen der Physik and Helmholtz' deepening respect.""To encourage experimental work in the notoriously difficult domain of unclosed currents, Helmholtz proposed for the prize of the Berlin Philosophical Faculty in 1878 a problem dealing with an implication of Weber’s theory: when oscillations of electricity are set up in an unclosed circuit, Weber’s hypothetical electrical inertia should reveal itself in a retardation of the oscillations. Through the experiments that Helmholtz had suggested on the self-induction of doubly wound spirals, Hertz won the Philosophical Faculty prize"" he proved that the inertia of electricity is either zero or less than a very small value, thereby lending experimental support to Helmholtz’ theoretical judgment of the improbability of Weber’s theory.""(DSB).‎

‎Ueber die Grundgleichungen der Electrodynamik für bewegte Körper.‎

‎Leipzig, Johann Ambrosius Barth, 1880. Without wrappers as issued in ""Annalen der Physik und Chemie. Hrsg. von G. Wiedemann."", Neue Folge Bd. 41, 11. Heft. Pp. 369-640 (entire issue offered, Heft 11). Hertz's paper: pp. 369-399. cLEAN AND FINE.‎

‎First edition of this importent paper in which Hertz went beyond Maxwell and hereby took the first step on the way to RELATIVITY THEORY.In his second theoretical paper (the paper offered), Hertz applied Maxwell’s equations to moving, deformable bodies. Maxwell had not treated this problem systematically in the Treatise although, unknown to Hertz, he had done so elsewhere. Hertz recognized that to develop an electrodynamics of moving bodies, it was first necessary to specify whether or not the ether moves with bodies. For his part he would assume that the ether is mechanically dragged by moving bodies. The first ground for this assumption was that within the restricted domain of electromagnetic phenomena there was nothing incompatible with the idea of a dragged ether. The second ground was that its denial entailed the complication that two sets of electric and magnetic vectors had to be assigned to each point of space, one for the ether and one for the independently moving body. He recognized at the same time that a dragged ether was an unsure foundation for electrodynamics....""(DSB).Schilpp ""Einstein"" pp. 31 ff. - Whittaker ""A History of the Theories of Aether and Electricity"", pp. 328 ff.‎

‎Ueber die Einwirkung einer geradlinigen Schwingung auf eine benachbarte Strombahn. (+) Ueber Inductionserschneinungen, hervorgerufen durch die electrischen Vorgänge in Isolatoren. (Aus den Sitzungsber. der Berl. Acad. vom 10. Nov. 1887, mit einem Zusa...‎

‎Leipzig, Johann Ambrosius Barth, 1888. Conemp. hcalf. 5 raised bands, gilt spine and gilt lettering to spine. A few scratches to spine. Small stamp on verso of first -and general- titlepage and small stamps to verso of plates. ""Annalen der Physik und Chemie. Hrsg. von G. Wiedemann."", Neue Folge Bd. 34,. VIII,1048 pp. a. 8 folded engraved plates. (Entire volume offered). Hertz' papers: pp. 155-170, pp. 273-285, pp. 551-569, pp. 609-623.‎

‎First appearance of 4 famous and importent papers (2 of them in their final form) in which Hertz established by experiments the similarities between electric waves and light waves.""Hertz followed up his determination of the finite velocity of electric waves by performing a series of more qualitative experiments in 1888 on the analogy between electric and light waves. Passing electric waves through huge prisms of hard pitch, he showed that they refract exactly as light waves do. He polarized electric waves by directing them through a grating of parallel wires, and he diffracted them by interrupting them with a screen with a hole in it. He reflected them from the walls of the room, obtaining interference between the original and the reflected waves. He focused them with huge concave mirrors, casting electric shadows with conducting obstacles. The experiments with mirrors especially attracted attention, as they were the most direct disproof of action at a distance in electrodynamics. They and the experiments on the finite velocity of propagation brought about a rapid conversion of European physicists from the viewpoint of instantaneous action at a distance in electrodynamics to Maxwell’s view that electromagnetic processes take place in dielectrics and that an electromagnetic ether subsumes the functions of the older luminiferous ether."" (DSB)-. ‎

‎Ueber sehr schnelle electrische Schwingungen. (+) Nachtrag zu der Abhandlung über sehr Schnelle electrische Schwingungen.‎

‎Leipzig, Johann Ambrosius Barth, 1887. Without wrappers as issued in ""Annalen der Physik und Chemie. Hrsg. von G. Wiedemann."", Neue Folge Bd. 31, 7. Heft. With the titlepage to vol. 31. Pp. 337-544 a. 2 folded plates, (entire issue offered ""Heft"" 7). Hertz's paper: pp. 421-448 A. PP. 543-544. A Stamp on titlepage and verso of. Clean and fine.‎

‎First edition of Hertz's seminal paper on electromagnetic waves in which he empirically demonstrates Maxwell's equations. This discovery and its demonstration led directly to the invention radio of communication, television and Radar. The paper is the ""ANNOUNCEMENT OF THE DISCOVERY OF THE PRODUCTION BY ELECTRICAL DISCHARGE OF WAVES WHICH HAVE THE PROPERTY OF VERY LONG WAVES""(H.M. Evans).Hertz demonstrates what Maxwell had predicted that electromagnetic waves radiated in space with the speed of light. Hertz determined these waves to be of greater length than light and that they could be reflected.""Experimental proof by Hertz of the Faraday-Maxwell hypothesis that electrical waves can be projected through space was begun in 1887, eight years after Maxwell's death. The two main requirements were (a) a method of producing the waves, supposing that they existed, and (b) a method of detecting them once they were produced."" (PMM, 377.). In the present paper Hertz ""describes the apparatus that he had devised for the detection and measurement of electromagnetic waves, the key to his later success. To prove that electromagnetic waves can be projected through space it was necessary to devise a means of both producing the waves and, more difficult at the time, of detecting them once produced."" (Norman Library, No. 1123).""Hertz's researches on electrical waves vindicated the Helmholtz ideal of the physicist as one whose competences embraced both experiment and mathematics. Hertz entered physics at the right time for one of his abilities to make a critical contribution"" because the outstanding problem of physics was the disorderly condition of electrodynamics, what was needed was someone with the theoretical power to analyze the competing theories and with the experimental judgment to produce the evidence that would persuade the physical community that a decision between the theories had been reached."" (DSB, VI, 348b.)""In the early 1890's the young inventor Guglielmo Marconi read of Hertz's electric wave experiments in an Italian electrical journal and began considering the Possibility of communication by wireless waves. Hertz's work initiated a technological development as momentous as it physical counterpart."" (DSB, VI, 349a.).‎

‎Sciences de la Vie et de la Terre 6e‎

‎Hachette Collections 2026 208 pages 20 8x1 2x27 6cm. 2026. Broché. 208 pages.‎

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‎A Place in History: Social and Monumental Time in a Cretan Town (Princeton Studies in Culture/Power/History)‎

‎Princeton University Press 1991 326 pages 15 494x2 286x23 114cm. 1991. Broché. 326 pages.‎

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‎Comme neuf‎

‎Recherches sur les quantités de chaleur dégagées dans les combinaisons chimiques. Lettre de M. Hess à M. Arago.‎

‎(Paris, Bachelier), 1840. 4to. No wrappers. In: ""Comptes Rendus Hebdomadaires des Séances de L'Academie des Sciences"", Tome X, No. 19. Pp. (721-) 775 (entire issue offered). Hess' paper: pp. 759-763. A few scattered brownspots.‎

‎First apperance of the announcement of Hess' newly discovered law, known as Hess's Law, in form of a letter to Arago. ""Here thermochemistry received its first importent advance at the hands of Germain Hess, who showed that the heat evolved in a reaction is the same regardless of whether the reaction is carried out directly or in a number of steps..."" (Leicester & Klickstein ""A Source Book in Chemistry"", pp. 329-332). This announcement preceded the larger paper published the same year in ""Annales de Chimie et de Physique"" and the original (and larger) paper in ""Bulletin scientifique, Academie impériale des Sciences (St. Petersbourg)"". Parkinson ""Breakthroughs"" 1840 C.‎