The history of the autoharp and other chord zithers is replete with innovations that were patented in one country and appeared shortly afterward in a patent issued in another country. When the dates are close enough, it can be difficult to determine who should be credited with the actual invention. Similarities do sometimes appear to be coincidental but plagiarism was common enough. One way of disguising it was to “extend” an earlier patent for a similar device to include the co-opted later innovation. Since the date of such revision was also recorded, this only partially obscured the actual priority.

Another technique was to label an instrument with the number or date of a patent that didn’t actually cover the design detail it was alleged to protect. The initial version of the present post exemplified this with the way Charles Zimmermann used the number and date of a US patent issued to him on 9 May 1882. The patent claims are quite specific in the details of the damping bars and soundbox design of the “autoharp” that it introduced, literally and musically. Both design details were changed substantially in the instruments he subsequently began producing on a large scale. Nonetheless, he labeled them with his initial patent coordinates.