I think I've found the origin of Mathiesen's claims about Emma's work as a "music critic" under the pseudonym Ernest Reinhold. It's to be found in Lewis Spence's Encyclopedia of Occulism and Parapsychology:
Interestingly enough, there does appear to be evidence (yet to be tracked down) that this claim is valid. Richard Kitson's vast The Musical World: 1836-1865 contains at least two references to music written by an Ernest Reinhold in that period: one, a popular song called "Pray for me, Gabrielle" (published by T. Boosey and Company, a London-based publisher operating continuously from the 1820s until the late 1850s) and another represented by the cryptic string "64:440r REINHOLD Professor Longfellow, the music composed by Ernest Reinhold (C. Jefferys)"
This second reference I find particularly intriguing because the Library of Congress holds the earliest published (musical) work known by EHB, The footsteps of angels: recitative and air (New York: H Waters, 1856), which appears in this advertisement from the Auburn (New York) American for some as-yet-undetermined date in 1858:
As the ad clearly indicates (which the LOC catalog entry does not), the words of the song are almost certainly those of
this poem of Longfellow's.
If the same words and music can be identified published under both Emma Hardinge and Ernest Reinhold, then we have a link that I think justifies trolling through the volumes of the Court Gazette for the years 1835-1842 looking for Reinhold's critical pieces.
Dig, dig, dig....and find
this....now purchased for the Archive.
The Court Gazette and Fashionable Guide (one of two places Mathiesen locates Ernest Reinhold's musical criticism, was (published in Catherine Street, and ran from April 7, 1838 until January 4, 1840, when it changed its name to New Court Gazette: A Fashionable Guide for January 1840 through December 26, 1840, when it became Court Gazette: The Only Fashionable Family Newspaper (January 1841 - August 1841), before folding.
Labels: Emma Harding, Emma Hardinge, Emma Hardinge Britten, Emma Hardinge-Britten, Ernest Reinhold