At the Guardian, a quite wonderful little essay by Daniel Kehlmen about reading and writing historical fiction. Here he describes visiting the observatory at Gottingen and seeing Gauss's telegraphic apparatus, which figures in the pages of his novel Measuring the World (it was already on my mental list, but now I definitely must read it):
This telegraph apparatus crops up in a scene towards the end of my novel. Professor Gauss, by this stage old and frail, is standing at the window of his study transmitting messages. He is half conversing with his colleague Weber and half with himself, but at the same time is in contact with the world of dead souls, a realm that has grown alarmingly over the course of his life. However, as the briefest glance at the machine in the observatory told me, it would have been impossible to hold conversations using this piece of equipment. The oscillations of the receiving needle were so faint that you had to stare down a magnifying tube to detect any movement against a scale. This in turn meant that the person transmitting the message had to send a messenger to the recipient beforehand to let them know when he planned to begin the transmission - a truly Pythonesque arrangement. As I stood there in Gauss's room, between the teleprinter, the window and the portrait, I made up my mind to stick to my original version.