A couple of years ago we, the museum group, collectively put together a case of objects designed purely to show of the diverse range of artefacts our university holds for the exhibition Hidden Histories. Everyone chose an object, wrote a blog post, filmed a youtube video and wrote a label. Put together and it gave a hint of our interests and knowledge, of how objects might lead you to interesting questions, and how varied yet largely uncelebrated was the University’s history.
That was two years ago. Now the team has changed, and our knowledge of the collections has grown. Also, for conservation reasons and to keep people looking at the case, its time for a revamp. As before, everyone is choosing an object and writing about it. Research has begun. Here is my contribution.
Perhaps not the most promising display item you might think, but these two, both from school classrooms in the late 19th-early 20th centuries, are pretty beautiful I think. The first:
The Poggendorff Cell nicely shows the basic workings of a cell. Its comprises a glass bottle and electrodes. When working it would be filled with dilute sulphuric acid saturated with potash bichromate which for obvious reasons have been removed for display purposes. The electrodes are made of carbon (+) and zinc (-). It was invented by Poggendorff in 1842 and if you’ve ever made a ‘battery’ (or more accurately a cell) from a lemon or a potato then you can probably work out how it works. When the electrodes are lowered into the acid, the positive electrode attracts ions in the acid, combines and releases electrons which are then attracted to the negative electrode and so it goes on. The flow of electrons is electricity.
The dry cell:
Came along a little later than the Poggendorff cell but works on a similar principle except that it uses a paste instead of liquid acid. Although this Siemens Brothers dry cell looks rather large to us, it is otherwise very similar to the ones we all have running various gadgets in our homes.
From a safety point of view, you can see, when you look at the Poggendorff battery why many people were apprehensive about allowing electricity into their homes in the early days. The first homes to install electric lights and so on did so in the 1880s. By the 1950s there were still homeowners who didn’t trust it preferring to use gas. For more on this story see our Lights on at Lotherton! collaborative project with Lotherton Hall (on going) based on research by Prof. Graeme Gooday published in his book Domesticating Electricity.