I am not an attorney, but it appears the atlas you mentioned
falls under the category of "public domain".
Here are some quotes from "Getting Permission: How to
License & Clear Copyrighted Materials Online & Off" by
Attorney Richard Stim, which is a book available for
purchase at
http://www.nolo.com
"The term "public domain" refers to creative materials
that are not protected by intellectual property laws such
as copyright, trademark or patent laws. The public owns
these works, not an individual author or artist. Anyone
can use a public domain work without obtaining permission,
but no one can ever own it."
....
"There are four common ways that works arrive in the
public domain:
* expiration of copyright: the copyright has expired.
* ....
* ....
* ...."
"Copyright has expired for all works published in the United
States before 1923. In other words, if the work was
published in the U.S. before January 1, 1923, you are free
to use it in the U.S. without permission."
I guess the only remaining question is:
Where was the atlas published? In the United States or
in England?