Do Research Papers have Public Domain Expiration Date?
From your question:

This is an article published more than 150 years ago. How long do I have to wait in order to download it and use it for free?

From a comment you posted:

Yes, I know I do still have to cite it, but I can't download it or use it for free. I have to pay even when it was published in the 19th century

As Buffy and anpami note, the original work probably isn't under copyright. But even if copyright has expired, there's no guarantee anyone will make it available for free. In particular, there is no obligation on the publisher to provide free (or indeed any) access to it.
In this case, there is a link to a PDF version from the Semantic Scholar page.