The "New Musical Wonder" is the nickname George Washington Stivers gave to the Humanatone. While this commercial name was stamped on the very early instrument, it was also used in the 1920's user manuals, and also declined as "The Wonder of the Musical World" (but strangely not in the earlier ones).
From a 1920's user manual:
So, as you can see, I have been greatly fortunate to find a sample of this wonder – I had been searching one for 7 years – and the cherry on the cake is that it is in a quite good condition. The nickel plating is well conserved, the stamping is neat and crispy, there is no rust spots and the shape itself is well preserved. Not mint, but museum grade.
The stamping mention a "trade mark" but no patents numbers. As far as I know, it is the first model of Humanatone without any mention of the patents. Geo's son James Joseph was in charge of the brand registering. He filed the application July 1, 1904 (trade mark No. 43,264 registered August 30, 1904) but mentioned in the document that "this trade-mark has been continuously used in [his] business since July 6, 1903.
On the other hand, I had been able to date an early Humanatone (check here please) of 1905-1911, with a logical preference for 1908-1911. This New Musical Wonder dates of before (no patent stamping) and should logically be the first model of nose flute stamped Humanatone. It should follow the (American) Magic Flute – probably designed by G. J. Couchois – which was (still) in the catalogues in 1903.
So, this super-early Humanatone should date of 1903 to ca.1908, with very probable time frame of 1903-ca.1905 (no stamping, etc.). Who designed it ? Couchois before selling patents to the Stivers, or the Stivers themselves ?