This is, perhaps, the most famous physics photograph showing the conference held in Brussels in 1927 and chaired by Hendrik Lorentz. The theme of the conference was photons and electrons, and the delegates struggled to understand the meaning of the new quantum mechanics.
Here I will describe how I obtained that photograph and will make a guess that maybe it was through my discovery that this picture came to light. I might be wrong about this and I invite people to correct my story and help with details but I found this photo almost forty years ago in a dusty corner.
My post-doc years were spent as a resident theoretician at the Kamerlingh Onnes Laboratory in Leiden, Holland. I worked in the molecular physics group of Professor Jan Beenakker. He had a large team and we studied the effects of electric and magnetic fields on the transport properties of gases. (You could actually see quantum effects in the viscosity and thermal conductivity in the gas phase.)
During the Napoleonic wars in 1807 a barge laden with gunpowder exploded in a canal near the center of the town. Five hundred people died and the explosion was heard as far away as Harlem. About a hundred years later, the Kamerligh Onnes laboratory was built on this site over the rubble of the destroyed buildings. The scientist, Kamerligh Onnes, was the first person to liquefy helium, and he went on to discover super-fluidity and super-conductivity.
The deepest part of the lab resembles a catacomb and I was told that in WW II, a couple of Jewish scientists hid there. In 1974, towards the end of my 2 years as post doc, I started to poke around and learn more about the lab’s history. In the Erenfest Reading room (a place where no books can be taken out because Erenfest said that he did not want the journals to end up in the offices of Profs, and unavailable to students), I found articles by famous physicists. I recall being particularly enthralled by the hand written thesis of Henri Poincarrié just sitting in the stacks. In those dark and dusty areas of the lowest level, there were boxes and crates that likely held treasures from the past research. However the best find for me was in the photographer’s storage area where a pile of glass negatives were stacked in a corner, some broken, but many intact. All were large so prints were made by direct contact.
In that pile, I found the original glass negative of the 1927 Solvay Conference. I had never seen the picture before and it was an exciting moment as I looked at my find, and started to recognize individuals. I talked to the current photographer, whose name I have now forgotten, and he kindly made prints of several of those negatives, including the Solvay conference. It came as a surprise when he told me that the person who took the Solvay Conference photograph was his grandfather.
Now I do not know what happened after that, but I know he made several copies at the time he made mine, and likely he just gave them away, and so, perhaps, the photo spread.
At least I like to think that it was my rummaging around that led to that photograph being discovered.
If anyone knows more, can debunk my theory; know the name of the photographer; or any other details about the origin of the picture, I would be very interested to hear from you.