The secret mission to unearth part of a 142 year old experiment

Here's another cool find from a DITer.

It seems that an experiment has been going on for 142 years!!

Imagine that!

So why was this a secret mission?

And what kind of experiment takes 142 years.

Today's click through explains.

HERE'S THE LINK TO The secret mission to unearth part of a 142 year old experiment