The Heptameron of Margaret, Queen of Navarre, translated by Walter K. Kelly (1855).
Available FREE texts:
There is also a lovely edition online as part of A Celebration of Women Writers at the University of Pennsylvania's Digital Library.
Other online sources:
Kindle eBook: $2.99
In addition, the translation by George Saintsbury is available at Project Gutenberg.The Saintsbury translation is the one available at Librivox.