Harpsichords and Clavichords, by Cynthia A. Hoover, 1969
https://www.gutenberg.org/files/39690/39690-h/39690-h.htm
I guess these are coming out of copyright after 50 years, perhaps.
It was available as pdf some 12 years ago, when I downloaded it to my pc. I didn’t note the source, sorry.
Dale
Perhaps the copyright period was shorter. I am no expert. Anyway, nice paper.
I have a copy of this that I bought at the Smithsonian when I visited and played the collection back in the '70s.
Are you out of copyright James, then? I think I am. 
What instruments did you admire the most there?
I am definitely out of copyright!
It’s been years since I played the Smithsonian collection. The first time I went, Ms. Hoover herownself was still there. She sat and listened to me play to make sure I didn’t damage the instruments, which was rather intimidating, since I’m an amateur and never did play very well. I remember playing the Dulcken, which was not very resonant, the Stehlin, which was very flutey, the deQuoco, and the Hitchcock spinet. Surprisingly, I recall liking the spinet the best, but that was a long time ago, and I was very young and inexperienced.