You missed by a year.

Anything published before 1922 is, as a general rule, public domain.

Until 1978, US copyright was limited to 28 years plus another 28 if renewed. A new law in 1978 extended copyrights then in force for a lot longer. But it couldn't revive copyrights that were already dead.

That's just in US, of course. Other countries have their own rules.

Peter.