Update
Updating database... Please wait.
Thursday 15 September 2016 at 17:22
True to the ideas held within — that blue light is bearer of unique and special properties — this book is entirely printed with blue ink on blue paper.
Source: http://publicdomainreview.org/collections/the-influence-of-the-blue-ray-of-the-sunlight-and-of-the-blue-color-of-the-sky-1877/