The Internet Archive has digitized the published works of Francis Grierson and made them available for free download.
In 1899, Francis Grierson published his first book, Modern Mysticism. Grierson's final published book was Psycho-phone Messages in 1921.
Link to Psycho-phone Messages in Internet Archive. https://archive.org/details/psychophonemessa00grierich
Grierson's final two works were never published.
Perhaps, I can do something about that...