Brüche was born in Hamburg, Germany, on 28 March 1900, but, on the death of his father in 1914, the family moved to Sopot near Danzig (then part of the German Empire, but today Gdansk in Poland). There, at the technical university, he studied mechanical engineering before switching to physics under the guidance of Carl Ramsauer, a highly regarded research physicist. He remained at the university, teaching while continuing research on the measurement of electron scattering cross-sections of molecular gases. In 1929, he married Dorothee Lilienthal with whom he had three daughters.
From 1928 to 1945, Brüche was head of the physics laboratories at the Allgemeine Elektrizitäts-Gesellschaft (AEG) where he worked mostly on geometrical electron optics and on developing an electron microscope. In 1944 he launched Physikalische Blätter, an academic physics journal, and remained its editor until 1972. From 1946 to 1951, he was head scientist of the Süddeutsches Laboratorium in Mosbach, north of Baden-Württemberg, and from 1948, he was the managing director of Physik-GmbH also in Mosbach. In 1952 he founded Physikalische Laboratorium Mosbach.
Brüche seems to have kept a diary at some points in his life. A few translated extracts have been published in Klaus Hentschel’s The Mental Aftermath: The Mentality of German Physicists 1945-1949 (Oxford University Press, 2007). Some pages can be consulted at Googlebooks. Here are several extracts from Brüche’s diaries as found in Hentschel’s book.
19 April 1945
‘We sit there in the forecourt of the Krügel building on a tree-trunk in the sun and feel like prisoners, which of course we are. We live under the most primitive conditions but even worse may well be in store for us. [. . .] Inside the factory no one wants to work anymore. It’s so pointless. Do what, and what for?’
22 April 1945
‘All in all I have got an image of Americans as a rich nation of high technological standards. Proud, unapproachable, and in everything technically superior and efficient. [. . .] We are sluggish, chase after ideals that in reality are completely different from what we think and we don’t even notice. We have a tick tor exactitude and don’t let ourselves be convinced that the others have long since found a simpler way that might not stand up to German criticism but leads more quickly to the goal and has been followed with success.’
28 June 1945
‘We don’t understand the Americans and they don’t understand us. [. . .] We will have to continue to strive and work, so that they see that all of us had not been Nazis and that it is for their own good that they don’t commit the same error with the Germans that we committed with the Jews.’
30 June 1945
‘Hilsch spoke for 4 hours long to two Englishmen and even if only 1% of it stuck, Saul must have turned into Paul. Lt. Comr. A. Elliott, RNVR, was the higher ranking of the two, who both listened with great interest to Hilsch’s portrayals of the stance of physicists toward the party. Hilsch said what any other physicist would also have said. But whether just any physicist would have taken such pains with 2 Englishmen is very doubtful.’
13 July 1945
‘I woke up during the night and had to think of all the misfortune in Germany. About Reinhold’s death, about ruined Berlin, about the terror we all have of the Russians, of the disinterested Americans, about Germany’s suicide, the death of German physics, and the absolute uncertainty of our fate. Isn’t it terrible to think: Russians in the cities in which Bach, Goethe, Haeckel, and whatever else their names are, lived and worked? My heart throbbed and tears almost welled up in my eyes.’
27 August 1945
‘These people remind me somehow of playing children, giant children, who thanks to their great strength have occasion to play with the Germans. It is cat playing with mouse. Does the cat realize at all that it is hurting the mouse when it allows the mouse, half dead as it is, to run a little more for its dear life so that it can catch it again? Why this disinterestedness by a nation that has taken upon itself the responsibility along with the power? Is this a game or cold calculation by the leadership? We want to work and rebuild. Why don’t they allow it? Why aren’t the trains running yet? Why is the post unusable and the telephone line broken? The Americans have been here for four months, four months of “peace” - and we are still waiting for peace. We are living off capital. Raw materials and supplies are everywhere lacking.’
11 October 1945
‘These mindless dismissals of all former Nazis could drive one to desperation. The method only shows that the Americans are no smarter than their predecessors, the Nazis. What did a reasonable man say to me yesterday? From a mild dictatorship with its faults we have now arrived at a severe dictatorship.’