The Oxford University It is a centennial place that could tell us many stories. Hence great minds like Stephen Hawking or Tim Berners-Lee and has always been an example of human knowledge. Not for nothing, it has 28 prime ministers Englishmen among his former students and 72 Nobel Prizes. Even its origin is surprising, since it dates from 1096, being the oldest English university and the second oldest university in the world still standing.

Within this University with capital letters is the Clarendon LaboratoryNot to be confused with the building of the same name. This laboratory currently consists of two buildings and is part of the Physics department from Oxford University. It has been in operation since 1872, making it the oldest physics laboratory in England. Its name, Clarendon, is due to the person responsible for its construction, Edward Hyde, 1st Earl of Clarendon.

But this story does not begin in 1096 or 1872. The story of the Oxford electric bell begins in 1825, when it was built. And its greatness is because since was launched in 1840, continues to work as the first day. That a device works for so long has merit. But it is that, in addition, it does not connect to the electrical network. It works by a battery.

A bell that you can’t hear

Actually the oxford electric bell it’s not one but two. Two small brass bells that ring in contact with a spherical metal piece that hits them as it oscillates between them. This piece, which is known in Spanish as clapper, remains hung between the two bells, which, in turn, are below two dry cells, connected in series. Another detail is that if you go to Oxford to visit it, you won’t be able to hear itAs it is kept quiet behind two layers of glass. Of course, you can see it in one of the hallways of the lobby of the Clarendon Laboratory next to a brief paper that says “dry cell demonstration” and that was “bought in 1840”.

The hood was created in the company Watkins and Hill From london. One of his physics teachers, also a cleric Robert Walker, was responsible for bringing this curious bell to Oxford University. Since then, the bell will have sounded about 10 billion times, according to some calculations. Of course, at a oscillation frequency of 2 hertz.

The purpose of this electric hood was not much to theorize about the perpetual motion, something that has been talked about a lot and that, for the moment, we have not been able to put into practice. For the moment, only fiction has managed to create machines of this type. What was intended to be studied with the Oxford bell were two theories related to electricity: the contact voltage theory, already overcome, and the chemical action theory or electrochemistry, the branch of science responsible for the current batteries in your phone, your laptop or your electric vehicle.

A stack you can’t open

The main mystery that revolves around this bell is what components do they carry the dry batteries that make it work. There are some clues, such as silver or zinc, but the exact composition is unknown. Yes, the batteries are protected with molten sulfur to isolate them and thus avoid their degradation over time.

Going back to its composition, the only way to know what your batteries contain, at the moment, is to disassemble the hood, is something that has been completely ruled out. It would ruin an involuntary experiment that has been running since 1840. Yet, in 1984, a researcher from the Clarendon Laboratory itself, AJ Croft, emphasized the layer of molten sulfur that protects the voltaic cells and the electrolyte. That is, it is not so much the inside of the battery itself as the external protection that preserves its conservation.

Of course, we know one of the causes that have made this bell last so long is the way it works. The key is in the electrostatic force which causes the metallic ball of only 4 millimeters in diameter to be attracted to one of the batteries, hit the bell, be repelled by the electrostatic force and repeat the process over and over again. So on. This operation consumes a small part of the battery power.

And as for what kind of cells or batteries the Oxford bell works, the answer lies with the Italian physicist. Giuseppe Zamboni, the creator of dry cells or Zamboni cells.

The first cells and batteries

Let’s travel back in time to know the origin of the cells and batteries, at least the first that were created. The first stop is 1780, year up, year down. In that decade, the Italian physicist Luigi Galvani discover the bioelectricity. The experiment is a classic in high school movies and series: you dissect a dead frog, connect its nerves with a metal object and, et voilĂ  !, the frog moves.

Let’s jump to 1800. The first chemical battery in history is born. His father is another Italian physicist,. Alessandro Volta. Based on Galvani’s knowledge, he designs what we know as voltaic pile, in honor of its name, or dry cell. It basically consists of stack copper and zinc discs alternately. Between both, cardboard discs soaked in brine or sulfuric acid. When the top and bottom are connected by a cable, an electric current is generated.

Third stop on this trip. 1812. The also Italian physicist Giuseppe Zamboni invent the Zamboni pile. Inspired by Volta’s voltaic cell, the Zamboni cell consists of paper discs coated with zinc foil on one side and manganese dioxide on the other. The moisture in the paper discs acts like an electrolyte. In practice, it is a battery or electrostatic battery.

And fourth and last stop. 1825, the year Watkins and Hill they design and create their electric hood. To feed it they use a Zamboni battery due to its durability and that its operation made it perfect for its work: feeding a metal ball that went from side to side.

In any case, even if we know what type of battery or cell is powered by the Oxford electric bell, we do not know when it will stop working. Time will tell. What is clear is that sooner or later the batteries will degrade and they will stop giving electricity. The question is whether we will be there to see it.

The article The electric bell that continues to play since 1840 was published in Explica.co.