German Physicist (88 results)

Condition: Near Fine. First edition hard back binding in publisher's original grey paper covered boards, red metallic title and author lettering to the spine, pale grey end papers. 8vo. 9½'' x 6¼''. Contains 216 printed pages of text with monochrome photographs throughout. Small mark to the fore edge. Near Fine condition book in near Fine condition dust wrapper with one small nick to the centre of the spine, not price clipped. Dust wrapper supplied in archive acetate film protection. Member of the P.B.F.A. ISBN 0246131586 ESPIONAGE (Clandestine).

Condition: Near Fine. First edition hard back binding in publisher's original grey paper covered boards, red metallic title and author lettering to the spine, pale grey end papers. 8vo. 9½'' x 6¼''. Contains 216 printed pages of text with monochrome photographs. Minimal marking to the closed page edges, small dent to the fore edge first 5 pages. Near Fine condition book in near Fine condition dust wrapper with rubs and creases, not price clipped. Dust wrapper supplied in archive acetate film protection, it does not adhere to the book or to the dust wrapper. Member of the P.B.F.A. ISBN 0246131586 ESPIONAGE (Clandestine).

Pas de couverture. Condition: Bon. Authentic photo (laser print) signed in the 90s. Size : 14.5x21 cm. Condition : see scans please. Certificate of Authenticity and lifetime guarantee. Signé par l'auteur.

(2), 56 pp. Printed wrappers. 8vo. Offprint from Annalen der Physik (Series 4, Vol. 30). Cover inscribed "with cordial greetings". The adjacent signature "Born" is not in the author's hand.

176 x 128 mm, annotated in pencil on verso: "Albert Einstein pl credit Lotte Jacobi 2299-2". A contemplative pose of Einstein in his famous leather jacket, holding his pipe, taken by Lotte Jacobi during the 1938 photo session she undertook with the theoretical physicist for Life magazine. - From the collection of Kalman Talansky (1924-2021).

176 : 128 mm. Albert Einstein and his famous bomber jacket. A contemplative pose of Einstein holding his pipe taken by Lotte Jacobi during the 1938 photo session she undertook with the theoretical physicist for Life magazine. - Photograph by Lotte JACOBI (1896-1990), Princeton, 1938.Annotated in pencil on verso: "Albert Einstein pl. credit Lotte Jacobi 2299-2".

4to. 1 p. Blind embossed letterhead. To the young aspiring Romanian physicist Melanie Serbu (1909-1979), in German living now in Zurich, Switzerland."I believe that the concerns of colleague Wenzel are entirely justified. What I wrote to you was just an insight, casually expressed without knowledge of the relevant specialized literature. Of course, I also don't have the time to engage with this literature and can, therefore, take no responsibility for the matter. However, it would probably be best to choose the topic of the dissertation in line with a colleague there. This way, you can be sure that the work will be accepted if it is completed to his satisfaction, whereas otherwise, you might risk expending a lot of effort in vain."Ich glaube, dass die Bedenken des Kollegen Wenzel durchaus berechtigt sind. Was ich Ihnen schrieb, war nur ein apercu, leichthin ohne Kenntnisse der einschlägigen Spezal-Literatur geäussert. Ich habe natürlich auch nicht Zeit, mich mit dieser Literatur zu befassen und kann deshalb in der Sache keinerlei Verantwortung übernehmen. Es dürfte aber wohl das Beste sein, das Thema der Dissertation in Einklang mit einem dortigen Kollegen zu wählen. Dann sind Sie sicher, dass die Arbeit angenommen wird, wenn sie zu dessen Befriedigung vollendet wird, während Sie sonst riskieren würden, eine Fülle von Arbeit nutzlos aufzuwenden.

4to. 1 page. To the German-American mathematician Ernst Gabor Straus. Einstein refers to a work he has just written in which he resolves the equations of the gravitational field issues from Bianchi's identities; he also congratulates Straus on a beautiful mathematical discovery and invokes by comparison the proof of transcendence of numbers that the latter had simplified. - An assistant to Einstein from 1944 to 1948, Ernst Gabor Straus detected a computational error in one of Einstein's works and, in order to correct it, wrote a paper with him in 1946 entitled "A Generalization of the Relativistic Theory of Gravitation". In 1949, having left his position with Einstein at Princeton University, he published "Some Results in Einstein's Unified Field Theory". The two scientists remained in a working relationship afterwards. - On headed paper; perfectly preserved.

4to. 1 p. Signature and one handwritten correction in green ink. In German. Framed, matted and glazed (46 x 62 cm) with a photographic portrait. To the Russian-French hydrodynamic engineer Wsevolode Grünberg in New York City, concerning a contested inheritance matter in which Einstein had reluctantly agreed to assist. From 1939, Einstein acted as a go-between for Grünberg and his friend János Plesch, an important Hungarian physician who had emigrated to England. "Concerning the inheritance matter", Einstein writes, "I regret having to report that we were not successful in getting my friend to England, as the War prevented it. Nor can I imagine that any hindrance remains to proceeding with the final settlement. I intend once more to encourage Mr. Plesch to put everything in order. As regards your inventions, I suggest that you send them for evaluation to my friend Professor Karman at the California Institute of Technology, who is a first-class expert and has influential connections to the realm of construction and practical implementation in the field. I enclose a letter to him [.]" (transl.). - Wsevolode Grünberg was the nephew of the Russian orthodontist and collector Josef Grünberg, a close friend of both Albert Einstein, who gave him the nickname "Bolshie", and János Plesch during their time in Berlin. It appears that Einstein and his second wife Elsa had become acquainted with Wsevolode Grünberg shortly before their friend's death in 1932. Travelling to America in 1939, Grünberg approached Einstein for an introduction to fellow engineers in the U.S. and help with his inheritance issue back in Europe. The two men met in June 1939 at the home of Irving Lehman in Port Chester, New York, and Einstein subsequently did what he could for Grünberg. In the early 1940s, Grünberg's important hydrofoil designs were used by the National Advisory Committee for Aeronautics (NACA) to build a seaplane model that was successfully tested at Langley, VA. Ironically, the classification of the project prevented the French citizen Grünberg from seeing the results of the tests until years after the war. Grünberg later became a U.S. citizen, changing his name to Waldemar A. Craig. - Traces of folds. On Einstein's embossed Princeton stationery.

4to. One page, 279 x 216mm. Blind embossed letterhead. In German. 'The controversy about the foundations of the physics of probability'. Einstein is sending in a separate packet the volume printed for his 70th birthday (Albert Einstein: Philosopher-Scientist). 'I am sending it to you as I think that the controversy about the foundations of the physics of probability will perhaps interest you'. Once Bergmann has finished with the book, Einstein asks him to pass it to Rosa Dukas, sister of Einstein's assistant, Helen. Einstein has been discussing the problems of the Hebrew University with the recently-elected president, Selig Brodetzky, who has visited. Selig Brodetzky (1888-1954) was second president of the Hebrew University during a turbulent period, marked by the forced abandonment of the campus on Mount Scopus and disputes with the University Senate.

4to. 1 page. Einstein on the value of relativity for philosophy. Einstein writes to Hans Reichenbach, the philosopher of science and an influential expositor of Relativity. In part (translation): "I am really very pleased that you want to dedicate your excellent brochure to me, but even more so that you give me such high marks as a lecturer and thinker. The value of the th.[eory] of rel.[ativity] for philosophy seems to me to be that it exposed the dubiousness of certain concepts that even in philosophy were recognized as small change. Concepts are simply empty when they stop being firmly linked to experiences. They resemble upstarts who are ashamed of their origins and want to disown them." The letter was published in the Collected Papers of Albert Einstein, vol 10, doc 66, pp 323-324 (CPAE Translation, vol 10, doc 66, p 201). Slightly uneven toning, a few spots in upper margin, two-hole punch at left margin, folding creases.

8vo. 1 p. on bifolium. Fine letter of the "father of acoustics" to his publisher Breitkopf & Härtel concerning two articles for the periodical "Allgemeine musikalische Zeitung" ("General music journal"), one of which is a review of Dalberg's work which was published in this year. His review, Chladni demands, shall be printed beyond his name; however, he was not successful for it was printed anonymously (vol. III, 1801, col. 196-200). - The second article (which was in fact "Ueber die wahre Ursache des Consonirens und Dissonirens") can be divided into two parts due to his lenght (col. 337-343 and 353-359). Moreover, he promises to send his review of Grétrys "Versuche über die Musik" ("Experiments in music"). - Tiny folding, and somewhat browned.

Pas de couverture. Condition: Bon. Authentic card signed in 2002. + Photo 10x15 cm (recent print). Size : 7.5x12.5 cm. Condition : see scans please. Certificate of Authenticity and lifetime guarantee. Signé par l'auteur.

Pas de couverture. Condition: Bon. Authentic photo signed in the 90s. Size : 9x15 cm. Condition : see scans please. Certificate of Authenticity and lifetime guarantee. Signé par l'auteur.

12mo: 2 pp. Very good. Addressed to 'Mr. W. Phillips' on otherwise-blank second leaf of bifolium, which carries traces of previous mount. Acknowledges 'the obliging present' of Phillips's 'valuable work on mineralogy' (the influential 'Outline of the Geology of England and Wales', 1822, written with William Conybeare). 'I have been for some time anxiously expecting the appearance of this new Edition [an earlier version had appeared in 1818] as I had given my last copy to a friend.' He is 'sorry the authorities are not sufficient to warrant the publication of the list I did myself the pleasure of sending you as an extensive table arranged in the order of specific gravities is I imagine, still a desideratum.'.

Pas de couverture. Condition: Bon. Authentic card signed in 1999. + Photo 15x15 cm (recent print). Size : 7.5x12.5 cm. Condition : see scans please. Certificate of Authenticity and lifetime guarantee. Signé par l'auteur.

One page, 8vo, two tiny closed tears, sl. dulled, mainly good condition. "I am trying to arrange a subscription for the Times and find that my newsagent cannot supply this unless an extra copy is allocated to him. I find it is essential for me to have the Times to keep sufficiently informed on what is going on. You have already been very helpful in arranging for a copy to be sent out to the British group, of which I was then in charge, at Santa Fe, New Mexico, and I would be very grateful for anything tou can do to accelerate the supply of a copy to me." He concludes with information about his newsagent. See Image.

Pas de couverture. Condition: Bon. Authentic photo signed in the 2000s. Size : 15x10.5 cm. Condition : see scans please. Certificate of Authenticity and lifetime guarantee. Signé par l'auteur.

1p, 4to. In good condition, lightly aged. With date stamp of the RSA. In response to a letter from Wood, he writes that he is 'highly honoured by the election to the membership of the Council of your Society', but that he is 'obliged to communicate to you my inability to accept it'. He explains: 'My work at the Royal Society has, in consequence of the War, increased to such an extent that I do not feel justified in undertaking any additional duties'. He notes that 'the meeting of Council are generally held on Mondays, that being almost the only day I have at present at home for the conduct of my private correspondence and outside work'.

2pp., 12mo. 37 lines of text. Bifolium. In fair condition, on aged and worn paper. The first sentence reads: 'Gegen das Projekt einer elektrischen Strassenbahn mit Erdleitung habe ich Einspruch erhoben und das Projekt ist von dem Polizei-Praesidium und von dem Ministerium fur offentliche Arbeiten untersagt worden.' The last paragraph refers to 'die Reichs-Telegraphic', 'Telephon', and 'Linien mit Erdleitung in Berlin', and contains a bar of music.

8vo. 1 p. Printed letterhead Fritz-Haber-Institut der Max-Planck-Gesellschaft". To Mr. Ancell: This is to draw your attention to the fact tht - to be sure - you'll find a lot of books about the method of measuring X-rays wave lengths in the Physical Dept. of your University of Albuquerque. []" - Laue was a German physicist who was awarded the 1914 Nobel Prize in Physics for his discovery of the diffraction of X-rays by crystals. In addition to his scientific endeavors with contributions in optics, crystallography, quantum theory, superconductivity, and the theory of relativity, Laue had a number of administrative positions which advanced and guided German scientific research and development during four decades. A strong objector to Nazism, he was instrumental in re-establishing and organizing German science after World War II.

Altogether 3 pp. 4to. Approximately 28 x 22 cm. An extraordinary testimony to the intellectual friendship between Albert Einstein and the mathematician Ludwig Hopf during the decisive months immediately before and after Einstein's emigration from Germany. The letters reveal cosmological reflections, personal humour, and Einstein's early warnings concerning the rise of National Socialism and the fate of Jewish scholars.The correspondence is addressed to Ludwig Hopf (18841939), Einstein's former assistant, whom he had first met at the ETH Zürich in 1910 and with whom he maintained a lasting scientific and personal relationship since their years together in Aachen. The letters document Einstein's cosmological thinking, his demanding international lecture schedule, and his increasing concern for the future of intellectual life in Germany under the Nazi regime.In the letter of 25 June 1932, Einstein explains the transition from a static to an expanding cosmological model, dispensing in this "first approximation" with both the cosmological constant and spatial curvature: "Seitdem man aus den Beobachtungen der Rotverschiebungen der extragalaktischen Nebel weiß, dass die Materie expandiert kann man den Gleichungen schon ohne -Glied und ohne Krümmung genügen" ("Since observations of the redshifts of extragalactic nebulae have shown that matter is expanding the equations can already be satisfied without the -term and without curvature"). Consequently, "man über die Existenz einer Raumkrümmung vorläufig nichts aussagen kann" ("for the present nothing can be said about the existence of spatial curvature").Alongside these scientific reflections, Einstein offers characteristically dry personal humour: "Die guten Berichte über Ihre Kinder freuen mich sehr Mir gehts auch ähnlich mit meinem jüngsten Sohn, der in der Musik ziemlich modernistisch verseucht ist. Der Ältere hat mich sehr respektlos zum Grosspapa befördert" ("The good reports about your children delight me greatly It is similar with my youngest son, who is rather infected with musical modernism. The elder has most disrespectfully promoted me to grandfather"). He also complains of having no time left for "Vergnügungs-Eskapaden" ("pleasure escapades").In the letter of 8 September 1932, Einstein apologizes for failing to answer an invitation, attributing this to the restless pace of his life during the final year of the Weimar Republic: "Zur Entschuldigung kann nur das Nomadenleben dienen, das ich in den letzten Monaten geführt habe" ("The only excuse can be the nomadic life I have led in recent months"). He regrets being unable to undertake a proposed lecture series because of his overwhelming travel obligations shortly before leaving Germany permanently in 1933.Particularly remarkable is the letter of 16 May 1933, written shortly after Hitler's seizure of power and Einstein's definitive break with German institutions. Attempting to help Hopf who would only succeed in emigrating to Cambridge in 1939 before receiving an appointment at Trinity College Dublin Einstein proposes an alternative professional future through international public lectures: "Sie sollen populäre Vorlesungen in verschiedenen Ländern und Städten über Relativitätstheorie, die Prinzipien der Hydrodynamik (Theorie des Fliegens), sowie über die Wandlungen der Atomtheorie halten" ("You should give popular lectures in various countries and cities on relativity theory, the principles of hydrodynamics [the theory of flight], and the transformations of atomic theory"). Such work, Einstein remarks, would not only be more profitable than a professorship but would also provide "ein amüsantes Zigeunerleben" ("an amusing gypsy life"). He offers to use his own international reputation actively on Hopf's behalf: "Sobald Sie es nur wollen, empfehle ich Sie überall hin, dass man Sie einladen soll" ("As soon as you wish it, I shall recommend everywhere that you be invited").Against the background of rapidly radicalizing conditions in Germany, Einstein formulates a strikingly sharp assessment of developments there: "Ich habe Ihre lieben Landsleute immer richtig eingeschätzt es wird bald gegen die intellektuelle Schicht überhaupt losgehen" ("I have always judged your dear compatriots correctly it will soon turn against the intellectual class altogether"). He laments that "Die Hochschulen sind überall auf den Hund" ("The universities everywhere are going to ruin") and refers to his then-discussed but ultimately unrealized project of establishing a Jewish refugee university: "Meinen Plan einer jüdischen Flüchtlingsuniversität habe ich so gut wie aufgegeben, weil er wenig Gegenliebe findet" ("I have more or less abandoned my plan for a Jewish refugee university because it finds little support").The correspondence concludes with practical questions concerning Hopf's language skills "Wenn nicht, dann büffeln Sie tüchtig" ("If not, then study hard") combining political seriousness with personal encouragement in a manner entirely characteristic of Einstein.An exceptionally important and historically revealing group of letters, uniting cosmological theory, exile history, intellectual friendship, and prophetic political observation during one of the decisive turning points of the twentieth century.

1 p. 4to. 28 x 22 cm. A deeply personal and affectionate letter to Einstein's younger son Eduard ("Tetel"), inviting him to Caputh in the hope of cheering him and strengthening his spirits. Combining paternal concern, philosophical reflection, and intimate glimpses into Einstein's private life, the letter is among the most human and emotionally revealing types of Einstein correspondence.Einstein writes that he will travel to Zurich on the 9th for "eine zionistische Sache" ("a Zionist matter") and proposes that Eduard accompany him back to Caputh, where he is living alone with Elsa in a small house by the lake: "Mein neues herrliches Schiff ist nun fertig und ich segle täglich. Es ist wunderbar für die Erholung" ("My splendid new boat is now finished and I sail every day. It is wonderful for recuperation"). Referring to the unusually cool weather, he suggests that the lakeside environment might benefit his son more than the mountains.The emotional core of the letter lies in Einstein's concern over Eduard's psychological condition and lack of vitality, which he senses between the lines of his son's recent letter: "Dein Brief bedrückt mich ein wenig, weil so wenig Unternehmungsgeist und Lebensfreude daraus spricht" ("Your letter depresses me somewhat because it shows so little enterprise and joy in life"). He stresses the moral and existential importance of meaningful work, invoking Arthur Schopenhauer as an example of a genius destroyed by the absence of practical occupation: "Selbst ein Genie wie Schopenhauer wurde zermürbt durch die Berufslosigkeit" ("Even a genius like Schopenhauer was worn down by the lack of a profession").Einstein continues with reflections of striking ethical clarity: "Man muss das Gefühl haben, dass man den anderen durch ehrliche Arbeit zurückgibt, was man empfängt. Sonst bleibt der moralische Katzenjammer nicht aus" ("One must feel that one gives back to others through honest work what one receives. Otherwise the moral hangover cannot fail to appear"). He concludes reassuringly that it will do Eduard good to spend more time in his company: "du wirst sehen" ("you will see").The letter was written during a transitional and physically fragile period in Einstein's life. Following a serious heart condition in 1928, he spent nearly a year recovering. In 1929 he built his celebrated summer house in Caputh near Potsdam, though at the time of the present letter he was still living in rented accommodation on Potsdamer Straße. The "new splendid boat" mentioned here was the sailing boat Tümmler, presented to Einstein by friends on the occasion of his fiftieth birthday in March 1929.Eduard Einstein (19101965), the second son of Albert Einstein and Mileva Mari , was highly gifted and musically talented. After excelling in his school examinations in 1929, he began medical studies with the intention of becoming a psychiatrist. Only a short time later, however, he developed schizophrenia, abandoned his studies, and spent much of his later life under psychiatric care at the Burghölzli clinic in Zurich.An exceptionally moving and psychologically revealing family letter, illuminating Einstein not as public icon or scientist, but as a deeply reflective and concerned father. From an important French private collection.

4to (222 x 280 mm). 2 pp. In pencil on cream-coloured paper with traces of perforation at top edge. In German. With the original envelope, addressed in ink. To the Polish German mathematician Chaim Herman Müntz (1884-1956), setting out several equations in the body of the letter: "Ich danke Ihnen bestens für die Mitteilung der allgemeinen Integrationsmethode für die Näherungsgleichungen, die zu der zweiten Hamilton-Invariante (Dichte) [.] gehört. Das ganze Problem liegt aber wesentlich schwieriger, als ich gedacht hatte [.] Damit hängt es zusammen, dass mir eine physikalische Interpretation der Theorie bisher überhaupt nicht gelungen ist. Es ist aber dabei im Auge zu behalten, dass gemäss Bohrs Resultaten der Zusammenhang zwischen der Bewegung der Singularitäten und dem Wellenfelde überhaupt nicht so einfach ist, wie es nach Maxwell sein sollte [.]". The letter closes: "Wenn ich wieder zurück komme, wollen wir ausführlich über die Sache reden. Man kann natürlich die ganze Bemühung als utopisch erklären. Aber eine mathematisch so natürliche Theorie ist ernsthafter Beachtung wert, zumal bei der gegenwärtigen disperaten Lage der theoretischen Physik" - a remark that appears to be levelled at the new developments in quantum mechanics. - A dense scientific communication from Einstein's Berlin period, aligning with his intensive work on a unified field theory in 1928-29 and reflecting his reliance on other figureheads of contemporary physics and mathematics. Müntz, noted for the Müntz approximation theorem, worked with Einstein from 1927 and is thanked in Einstein's paper "On Unified Field Theory" (1929) for "laboriously precise calculation on the basis of Hamilton's principle", underscoring the present letter's context. - A fine association piece at the intersection of physics and higher mathematics, documenting Einstein's ongoing attempts to ground unification in a Hamiltonian variational framework. - Folded horizontally and vertically; envelope torn open somewhat roughly at the side. - From a Swedish private collection. - The Collected Papers of Albert Einstein (Princeton UP, 2021), vol. 16, p. 389f., no. 245 (edited from a photocopy).

4to. 1 p. Printed letterhead Research Institutes | The University of Chicago". To Robert ancell in Albuquerque: The only proposal I can make to you is to try to get the yearly appearing reports of the Royal Swedish Academy of Science on the Novel festivity of each year. In these little books you will find also pictures and a brief biography of each Nobel Prize winner at the timethey received the Prize. I am sure you will find these books in every great university library or, at least, in the Library of Congress in Washington." - Franck was a German-American physicist who shared the 1925 Nobel Prize in Physics with Gustav Ludwig Hertz "for their discovery of the laws governing the impact of an electron upon an atom". He completed his doctorate in 1906 and his habilitation in 1911 at the Frederick William University in Berlin, where he lectured and taught until 1918, having reached the position of professor extraordinarius. He served as a volunteer in the German Army during World War I. He was seriously injured in 1917 in a gas attack and was awarded the Iron Cross 1st Class.

125 : 175 mm. Mounted to larger album page. Nice head and shoulders photograph of the physicist. - Maria Goeppert Mayer was a German-American atomic and nuclear physicist who shared the 1963 Nobel Prize in Physics with J. Hans D. Jensen and Eugene Wigner. One half of the prize was awarded jointly to Goeppert Mayer and Jensen for their model of the atomic nucleus. She was the second woman to win a Nobel Prize in Physics, the first being Marie Curie in 1903. In 1986, the Maria Goeppert-Mayer Award for early-career women physicists was established in her honor.

Black and white photograph, 100 x 150 mm. Heisenberg was one of the founders of quantum mechanics and was awarded the Nobel Prize for Physics in 1933. - The signature is written in blue ink below the photograph by the well-known German photographer Tita Binz (1903-70), bearing the stamp of her Munich studio on the reverse: "Tita Binz / 8 München 22 / Schackstr. 1". Accompanied by a blank white envelope. - Photograph and autograph in excellent condition.

4to (280 x 216 mm). 1½ pages. Dated (likely in the hand of Helen Dukas) in pencil at upper and lower right. The manuscript comprises approximately 31 lines of mathematical workings. Einstein devoted the last thirty years of his life to the quest to combine general relativity and Maxwell's theory of electromagnetism into a single physical and mathematical framework which would account for all of the then-known fundamental forces of nature - a "unified field theory". Although his early attempts in the 1920s focused on "distant parallelism", he later concentrated on an approach treating both the metric tensor and the affine connection as fundamental fields, often introducing an element of asymmetry (in variance to the theory of general relativity). Einstein often complained of the heavy mathematical burden imposed by this approach, as demonstrated in the present manuscript. - In mint condition. - Sotheby's, 30 May 1979, lot 49 (part).

4to. 1 page. In German. On blindstamped headed stationery. To the Hungarian-born physicist Cornelius Lanczos (1893-1974) at Purdue University, Lafyette, Indiana, about Lanczos's wave tensor, pointing out that it is indeed invariant in special-relativistic terms, but not the way in which it is constituted from individual waves of different frequencies; adding that his own research on complex space is not yet finished: "Nun noch eine Bemerkung über Ihren Wellen-Tensor: Es ist zwar richtig, dass dieser als Ganzes genommen spezial-relativistisch invariant ist, nicht aber die Art und Weise wie er aus Einzelwellen verschiedener Frequenz konstituiert ist [.] Meine Untersuchungen über den komplexen Raum sind noch nicht fertig". - Einstein further discusses his suffering from "bilious attacks", along with the challenges theoretical physicists face in finding defence work, and advises Lanczos to remain at Purdue University, as getting a job at the Institute for Advanced Study or elsewhere might prove difficult due to the lack of money there, compounded by xenophobia: "Ich glaube aber, dass Leute, die vorwiegend theoretisch gearbeitet haben, nicht so viel begehrt sind, besonders wenn noch die Xenophobie in Frage kommt". - Einstein's remarks about defence work are poignant: although the Einstein-Szilard letter to F. D. Roosevelt on 2 August 1939 effectively launched the Manhattan Project to construct an atomic bomb, he was himself denied clearance to work on it in July 1940, in part because of his pacifist views. In June 1943 he was, however, reported to be advising the Ordnance Bureau of the U.S. Navy on the theory of explosives. - Small tear to left margin.

4to. 1 page. In German. To the Hungarian-born physicist Cornelius Lanczos (1893-1974) with thanks for sending him a copy of his book "The Variational Principles of Mechanics" (1949) and for his having dedicated it to him, pointing out that it has freed him for the time being from the burden of being a passionate non-reader. Einstein ironically adds that despite everything he has learned so far about the American people he hopes the work will gradually find general distribution in U.S. universities: "Sie wissen, dass ich ein leidenschaftlicher Nichtleser bin. Aber Ihr Buch wird mich für eine Zeit von diesem Laster befreien [.] Ich zweifle nicht, dass dies Buch allmählich eine allgemeine Verbreitung in den hiesigen Universitäten finden wird, trotz allem was ich von unseren neuen Landsleuten allmählich in Erfahrung gebracht habe". - Returning to their shared obsession with gravitational theory, Einstein provides three equations which he now feels certain constitute the "overdetermined system" which is "the only natural generalisation of the gravitational equations". The reasoning that has brought him to this conclusion appears as an appendix in "the new edition of my old relativity book", which he will send Lanczos as soon as he has a copy. - Very well preserved.