a kind of box or container where you can store objects and information so that people in the future - yourself included - will know how we lived at that particular time
Yes the time capsule's items date from over 200 years ago, so the historians are concerned about opening it. The newspapers particularly might have deteriorated, decayed or decomposed over time.
Paper doesn't last long. But my old mobile phone - the one I'm going to put in my own time capsule - will be eternal, it means it will exist forever! And the historians of the future will be grateful!