Scientific experiments that have lasted a century or more

Over at Atlas Obscura, the editors have gathered together an incredible list of the longest-running scientific experiments in history. But we were most intrigued by two mechanical experiments that started during the nineteenth century and never stopped.

The first is the ultimate steampunk fetish - a clock that has been running continuously since 1864, without needing to be wound up:

Invented by Arthur Beverly, this ingenious piece of timekeeping has yet to be wound since being put into "near perpetual-motion" way back in 1864.

Its sealed glass casing contains a box that flexes with atmospheric pressure. It flexes just enough to propel the clock's weights, keeping it running, and creating one of the most sustainable, efficient timepieces the world has ever seen.

It takes only a six-degree Celsius temperature variation over a day to raise the one-pound weight an inch, powering the clock for yet another day. A commercial version of this type of clock is available under the name "Atmos Clock."

Scientific experiments that have lasted a century or more

And then there's the bell that has been ringing for almost two centuries:

In a scientist's version of an alarm clock hell, the Oxford Electric Bell (or Clarendon Dry Pile) has been ringing quietly, but constantly, for over 170 years.

Made of two dry pile batteries of unknown composition, a brass bell hangs beneath each battery. Started in 1840 the metal 'clapper' swinging between them has produced a ring that has occurred on the order of 10 billion times. It is unknown when the batteries will finally run down.

A double-thick glass bell jar muffles the ringing sound, and keeping those around the bell from trying to hit snooze.

Read the full list of longest running experiments, including some of a morally dubious nature, over at Atlas Obscura.

Beverly clock photo by Steve Jurvetson (flickr). Oxford Electric Bell photo by Leo Panthera (Wikipedia).