Back in Time with Thomas Edison (Qwerty Stevens Series)

Robert Edwards Stevens, nicknamed "Qwerty," likes digging in his backyard when he's in a bad mood. He doesn't dig for anything special -- he just digs to get his mind off things. One day, when he's really angry and has a lot on his mind, he starts digging...and THUNK! He hits something, a wooden box with a famous signature:
Thomas A. Edison
Is this a phonograph created by the famous inventor himself? Or is it something even more incredible -- something that could take Qwerty right to Thom...