That is very interesting. It appears to be a half-sized version of mine without legs. Mrs Virgil was apparently the wife of the inventor of the large version.
https://www.operas.com.ar/Music-Encyclopedia/89182/Virgil-practice-clavier.htm It still has lead in it, I presume, and is therefore pretty heavy to cart around ? Mine was supposed to be portable but that is ridiculous. It was hernia city just getting it into the house.
Come to think of it, for isolated finger work without jumping around, the small version would be very useful. Its value, as with mine, is problematical. For a pianist who really wanted it you could probably name your price, but very few such players are likely to exist. I once tried to value mine for insurance purposes but soon gave up. Most antique dealers hadn't the foggiest idea what it was.
Are you a pianist ? Is it in working order ? If so, if there isn't a pressing need to get rid of it, I would suggest just hanging onto it and using it. Even if it isn't in working order, those things are pretty simple and easy to fix. Of course if you do that, it is no longer regarded as a decent antique. On the face of it, I think yours might be a lot rarer than mine.
Topic: Vintage Mrs. A. M. Virgil Practice Keyboard