Try researching the writing on the instrument for a clue. I searched on Marshall and hit law schools in the US, but if you search "Mrs. Hartley Maud" this turns up:

Proceedings, Volumes 51-52, But Somersetshire Archaeological and Natural History Society (this volume housed in California).

Donations Towards the Taunton Castle Restoration and Deficit Fund
Since the Publication of Vo. LI of the "Proceedings," and up to December 31st, 1906.

Marshall, Mrs. (now Mrs. Hartley Maud)

The result is a free e-book through Google books. Taunton: Barnicott and Pearce, Athenaeum Press, 1906.

This is a bread crumb, but if the name and the period satisfy searchers that the woman named on the instrument is from the region this book is about, then it's back in your court. The instrument is from the UK.