What I would like to know is can this old battery power electrical devices (lights, motors, etc) with more electrical-resistance / a bigger load, and if so, for how long?  Knowing that may make this old design worth replicating (or not).  If it can, then that is way more important than its curiosity value.,(reply>), If you want a long running electrical circuit, do what the Russians did with their lighthouses in the northern arctic sea ... Atomic Batteries.<br><br>Or, if you only need a small amount of energy, make a system that scavenges energy transmitted by such sources as radio and television transmitters and cell phone networks.,(reply>), @Oldtwins The logical fallacy you have committed is called 'appeal to authority',(reply>), Leo Curious actually nevermind, I'm dumb. At the time scales I'm thinking of, a radioisotope sample would be more practical if less precise.,(reply>), A simple letter with a date code would do that job. And would be much more precise... aaand is known to really work that long.,(reply>), Leo Curious you could power a very basic digital stopwatch for a time capsule, that would tell people who find the time capsule how long it had been buried