A Calculus of Angels
A Calculus of Angels is an alternate history and fantasy novel by American writer Gregory Keyes, the second book in The [Age of Unreason] series. It was initially published by Del [Rey Books|Del Rey] on March 30, 1999. A follow-up to Newton's Cannon, the book is set in 1722 and continues the alternate history where Isaac Newton discovers that alchemy works, and a powerful science is built upon it.