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Autograph letter signed ('Albert') to Michele Besso, Prague, 26 March [1912]
Details
Albert Einstein (1879-1955)
Autograph letter signed ('Albert') to Michele Besso, Prague, 26 March [1912]
In German. Four pages, 225 x 145mm, and three pages, 171 x 111mm, including ten mathematical equations; concluding with a postscript of two pages by Mileva Einstein. Provenance: Stargardt, catalogue 627, 1982 – German private collection.
‘Recently I was working in a frenzy on the gravitation problem’ – the most substantial contemporary letter about Einstein’s early work on general relativity. Writing to his close friend and scientific ‘sounding board’, Michele Besso, Einstein explains in technical detail his first crucial steps toward a theory of gravity.
The letter is an articulation of the mathematical physics of Einstein's revolutionary new theory of the static gravitational field. The starting-point for this new theory of gravity was his 1911 paper ‘On the influence of gravitation on the propagation of light’ and its follow-up ‘The speed of light and the statics of the gravitational field’ (Weil 43 and 47), and these light-bending thoughts are still very much on Einstein’s mind. Testifying to Einstein’s thinking at the very birth of general relativity, the letter is the first known instance of him explaining the theory’s substance.
Einstein begins by informing Besso that he has ‘now got to the stage that I am finished with the statics. I still know nothing about the dynamic field: that will only follow now'. In talking Besso through the results of his work, Einstein begins by emphasizing that in his new theory of gravity – contrary to the special theory of relativity – the velocity of light (‘c’) is not universal and constant, but rather locally determined and variable: 'Time in field defined by the postulate that the velocity of light c depends, indeed, on the location, but not on the direction’. In this new theory the light-velocity function, c(xyz), ‘completely determines the gravitational field’: ‘All equations must be constructed accordingly’, Einstein warns – and time in particular must be understood in this context.
Einstein then launches into a mathematical articulation of the fundamental equations of his new physics. Deriving his formulas using the equivalence principle for gravity, Einstein explicitly gives the equations for the motion and energy of a material point (‘The energy of the point: mc/√(1-q2/c2’), and continues to a reframing of Maxwell’s equations of electromagnetism. ‘The fit [of these equations] with the customary theory of [special] relativity is staggering … From them follows the gravitation of the electromagnetic energy as well as all of the other influences of the gravitational field on electromagnetic process’. Einstein makes a special point of highlighting a central thesis of general relativity, that ‘the gravitational mass of a system depends on the kinetic energy of the relative motions of its parts in the same manner as the system’s inertial mass’.
In closing his mathematical exposition of the new physics, Einstein writes out the nonlinear equation of the static gravitational field and again draws attention to the extreme locality of general relativity: ‘Most interesting of all is the theory of the gravitational field itself, during the development of which it turned out that the principle of equivalence of acceleration and gravitation holds only for ∞ [the infinity sign = infinitesimally] small systems’. After making a few dismissive remarks about Max Abraham’s alternative theory of gravity – a theory which Einstein says ‘has been created out of thin air’ – Einstein returns to his own gravitational system and assesses his progress to date: ‘You see that I am still so far from being able to conceive of rotation at rest! Each step is devilishly difficult, and what I have derived so far is certainly still the simplest of all’.
Einstein concludes his letter with a two-page report on his major article 'Thermodynamic proof of the law of photochemical equivalence' (Weil 46, published on the same day as the letter), an experiment that effectively proved the existential reality of the photon.
The letter precedes the published statement of Einstein’s theory (‘On the theory of the static gravitational field’: Weil 48) – by almost two months, and it was in fact written just a week after he had sent the manuscript off. Einstein was tight-lipped about the specifics of his work with general relativity in the years before its completion in 1915, and typically his letters contain only the most general statements about his progress (or lack of progress). This letter is therefore uncharacteristically revealing about the particulars of his new theory, with a notably ebullient, excited quality to his tone, no doubt because Einstein was writing to such a close friend and scientific collaborator.
The recipient of the letter, Michele Besso (1873-1955), has a unique status in Einstein’s life: not only his closest friend and ‘sounding board’, Besso collaborated with Einstein in the formulation both of special relativity and general relativity. Einstein explicitly credited Besso for his ‘assistance’ and ‘valuable suggestions’ in the 1905 paper on special relativity, while Besso’s months-long collaboration with Einstein in 1913-14 in the calculations of the perihelion of Mercury, which empirically proved general relativity’s validity, constituted a significant contribution to the completion of the theory.
The general theory of relativity has been called ‘the greatest intellectual achievement of any one person’, and contemporaneous letters detailing Einstein’s development of relativity are of the greatest rarity in private hands. As the earliest substantial statement of its fundamental mathematical principles, this letter represents a monument in the history of science. It had clearly left the Besso family before 1972, as it was not included in Pierre Speziali’s edition of the Einstein-Besso correspondence, published in that year (indeed, no letters from 1912 were included in Christie’s 2017 sales of the Besso family’s holdings of Einstein letters). After being sold at auction in West Germany in 1982, it remained in a private collection until its recent reappearance. The letter is published (with the exception of Mileva's postscript) in the Collected Papers, 5, no. 377.
Autograph letter signed ('Albert') to Michele Besso, Prague, 26 March [1912]
In German. Four pages, 225 x 145mm, and three pages, 171 x 111mm, including ten mathematical equations; concluding with a postscript of two pages by Mileva Einstein. Provenance: Stargardt, catalogue 627, 1982 – German private collection.
‘Recently I was working in a frenzy on the gravitation problem’ – the most substantial contemporary letter about Einstein’s early work on general relativity. Writing to his close friend and scientific ‘sounding board’, Michele Besso, Einstein explains in technical detail his first crucial steps toward a theory of gravity.
The letter is an articulation of the mathematical physics of Einstein's revolutionary new theory of the static gravitational field. The starting-point for this new theory of gravity was his 1911 paper ‘On the influence of gravitation on the propagation of light’ and its follow-up ‘The speed of light and the statics of the gravitational field’ (Weil 43 and 47), and these light-bending thoughts are still very much on Einstein’s mind. Testifying to Einstein’s thinking at the very birth of general relativity, the letter is the first known instance of him explaining the theory’s substance.
Einstein begins by informing Besso that he has ‘now got to the stage that I am finished with the statics. I still know nothing about the dynamic field: that will only follow now'. In talking Besso through the results of his work, Einstein begins by emphasizing that in his new theory of gravity – contrary to the special theory of relativity – the velocity of light (‘c’) is not universal and constant, but rather locally determined and variable: 'Time in field defined by the postulate that the velocity of light c depends, indeed, on the location, but not on the direction’. In this new theory the light-velocity function, c(xyz), ‘completely determines the gravitational field’: ‘All equations must be constructed accordingly’, Einstein warns – and time in particular must be understood in this context.
Einstein then launches into a mathematical articulation of the fundamental equations of his new physics. Deriving his formulas using the equivalence principle for gravity, Einstein explicitly gives the equations for the motion and energy of a material point (‘The energy of the point: mc/√(1-q2/c2’), and continues to a reframing of Maxwell’s equations of electromagnetism. ‘The fit [of these equations] with the customary theory of [special] relativity is staggering … From them follows the gravitation of the electromagnetic energy as well as all of the other influences of the gravitational field on electromagnetic process’. Einstein makes a special point of highlighting a central thesis of general relativity, that ‘the gravitational mass of a system depends on the kinetic energy of the relative motions of its parts in the same manner as the system’s inertial mass’.
In closing his mathematical exposition of the new physics, Einstein writes out the nonlinear equation of the static gravitational field and again draws attention to the extreme locality of general relativity: ‘Most interesting of all is the theory of the gravitational field itself, during the development of which it turned out that the principle of equivalence of acceleration and gravitation holds only for ∞ [the infinity sign = infinitesimally] small systems’. After making a few dismissive remarks about Max Abraham’s alternative theory of gravity – a theory which Einstein says ‘has been created out of thin air’ – Einstein returns to his own gravitational system and assesses his progress to date: ‘You see that I am still so far from being able to conceive of rotation at rest! Each step is devilishly difficult, and what I have derived so far is certainly still the simplest of all’.
Einstein concludes his letter with a two-page report on his major article 'Thermodynamic proof of the law of photochemical equivalence' (Weil 46, published on the same day as the letter), an experiment that effectively proved the existential reality of the photon.
The letter precedes the published statement of Einstein’s theory (‘On the theory of the static gravitational field’: Weil 48) – by almost two months, and it was in fact written just a week after he had sent the manuscript off. Einstein was tight-lipped about the specifics of his work with general relativity in the years before its completion in 1915, and typically his letters contain only the most general statements about his progress (or lack of progress). This letter is therefore uncharacteristically revealing about the particulars of his new theory, with a notably ebullient, excited quality to his tone, no doubt because Einstein was writing to such a close friend and scientific collaborator.
The recipient of the letter, Michele Besso (1873-1955), has a unique status in Einstein’s life: not only his closest friend and ‘sounding board’, Besso collaborated with Einstein in the formulation both of special relativity and general relativity. Einstein explicitly credited Besso for his ‘assistance’ and ‘valuable suggestions’ in the 1905 paper on special relativity, while Besso’s months-long collaboration with Einstein in 1913-14 in the calculations of the perihelion of Mercury, which empirically proved general relativity’s validity, constituted a significant contribution to the completion of the theory.
The general theory of relativity has been called ‘the greatest intellectual achievement of any one person’, and contemporaneous letters detailing Einstein’s development of relativity are of the greatest rarity in private hands. As the earliest substantial statement of its fundamental mathematical principles, this letter represents a monument in the history of science. It had clearly left the Besso family before 1972, as it was not included in Pierre Speziali’s edition of the Einstein-Besso correspondence, published in that year (indeed, no letters from 1912 were included in Christie’s 2017 sales of the Besso family’s holdings of Einstein letters). After being sold at auction in West Germany in 1982, it remained in a private collection until its recent reappearance. The letter is published (with the exception of Mileva's postscript) in the Collected Papers, 5, no. 377.
Brought to you by
Eugenio Donadoni
Senior Specialist, Medieval & Renaissance Manuscripts